Myology of the Purple-throated Carib (Eulampis jugularis) and Other Hummingbirds (Aves: Trochilidae)

RICHARD L. ZUSI and GREGORY DEAN BENTZ

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S. Dillon Ripley Secretary Smithsonian Institution SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY • NUMBER 385

Myology of the Purple-throated Carib (Eulampis jugularis) and Other Hummingbirds (Aves: Trochilidae)

Richard L. Zusi and Gregory Dean Bentz

SMITHSONIAN INSTITUTION PRESS City of Washington 1984 ABSTRACT Zusi, Richard L., and Gregory Dean Bentz. Myology of the Purple-throated Carib (Eulampis jugularis) and Other Hummingbirds (Aves: Trochilidae). Smithsonian Contributions to Zoology, number 385, 70 pages, 20 figures, 1984.— All muscles of the axial and appendicular skeleton of Eulampis jugularis are described and illustrated, and comparisons are made with the Rufous-breasted Hermit (Glaucis hirsuta), the Fork-tailed Woodnymph {Thalurania Jurcata), the Velvet-browed Brilliant (Heliodoxa xanthogonys), the Giant Hummingbird (Pa- tagona gigas), the Tyrian Metaltail (Metallura tyrianthina), and the Bahama Woodstar (Calliphlox evelynae). These species were chosen to include the major taxonomic subdivisions within the Trochilidae. Although species with remark- able structural modifications of the bill, wings, and tail are excluded from this study, myological variation within the hummingbirds studied nevertheless suggests considerable potential for future studies of systematics and adaptation within the Trochilidae. Unusual features in hummingbirds are identified and compared with oscines (Passeriformes), swifts, and various other birds for future use in phylogenetic studies on the familial and ordinal levels. Hum- mingbirds are shown to lack 19 muscles or distinct parts of muscles found in some members of the Passeriformes.

OFFICIAL PUBLICATION DATE is handstamped in a limited number of initial copies and is recorded in the Institution's annual report, Smithsonian Year. SERIES COVER DESIGN: The coral Montastrea cavernosa (Linnaeus).

Library of Congress Cataloging in Publication Data Zusi, Richard L. (Richard Laurence), 1930- Myology of the purple-throated Carib (Eulampis jugularis) and other hummingbirds (Aves: Trochilidae) (Smithsonian contributions to zoology ; no. 385) Bibliography: p. Includes index. 1. Purple-throated carib—Anatomy. 2. Hummingbirds—Anatomy. 3. Muscles. 4. Birds— Anatomy. I. Bentz, Gregory Dean. II. Title. HI. Series. QL1.S54 no. 385 598.8'99 83-14794 [QL696.A558] Contents

Page Introduction 1 Methods 2 Terminology 2 Acknowledgments 2 Muscles of the Eye 3 Muscles of the Jaws 4 Muscles of the Tongue and Hyoid Apparatus 8 Muscles of the Vertebral Column 11 Muscles of the Trunk and Abdomen 18 Muscles of the Tail 21 Muscles of the Forelimb 23 Muscles of the Hindlimb 33 Subcutaneous Muscles 40 Discussion 41 Systematic Studies within the Trochilidae 41 Phylogenetic Relationships of the Trochilidae 41 Muscles Absent in Hummingbirds 44 Adaptations 44 Literature Cited 45 Appendix 1: Index to Muscle Abbreviations 47 Appendix 2: Index to Abbreviations, Excluding Muscles 50 Figures 1-20 52 Index to Main Muscle Headings 69

Myology of the Purple-throated Carib (Eulampis jugularis) and Other Hummingbirds (Aves: Trochilidae)

Richard L. Zusi and Gregory Dean Bentz

Introduction sense organs) are not included except for two eye muscles. Broad comparisons throughout the Tro- Comparative studies of avian myology in re- chilidae have not been attempted here but six cent decades have dealt typically with muscles of other species of six genera are compared with the appendages or jaws within an order or family. Eulampis to determine major variation within the The purpose of these broad studies has been family. These genera (Glaucis, Thalurania, Helio- either descriptive or systematic and authors have doxa, Patagona, Metallura, and Calliphlox) were cho- not felt compelled to study the complete myology sen to include representatives of the main supra- of their subjects, perhaps because the task would generic divisions of the Trochilidae as determined be monumental for large and varied taxonomic by Zusi (in preparation). Thus our data can be groups. For systematic studies it has been stated used to represent the Trochilidae in comparisons or implied that, if the problem can be "solved" with other families. using only a portion of the bird, there is no need The purposes of this paper are several. One is to include the remainder. As a result the literature simply to put the myological data on record. The of avian myology contains a mosaic of data with literature on hummingbird myology is incom- numerous information gaps; for any given family plete and of mixed quality. Some aspects of myol- or order we are likely to find comparative studies ogy were studied long ago and are not readily of jaw muscles, hindlimb muscles, or forelimb accessible (wing: Buri, 1900; tongue and jaws: muscles, but rarely all three, and in no case Moller, 1931). Other more recent studies are par- comparisons of all skeletal muscles. tially in error (tongue: Weymouth et al., 1964) or This paper presents the description of all mus- essentially accurate but incomplete for the por- cles that attach on the axial and appendicular tion of the bird treated (neck: Burton, 1971; wing: skeletal systems in the Purple-throated Carib Fiirbringer, 1888; Cohn, 1968). We are not aware {Eulampis jugularis, Trochilidae). Striated muscles of any complete studies on the neck, trunk, tail, intrinsic to other systems (respiratory system, or hind limb muscles of a hummingbird. Another purpose is to serve as a guide for future Richard L. Zusi, Department of Vertebrate Zoology, National Museum studies on myology and systematics of humming- of Natural History, Smithsonian Institution, Washington, D.C. 20560. Gregory Dean Bentz, Mount Vemon College, Washington, birds. Until recently there has been no compara- D.C. 20007. tive myological work done within the Trochilidae, SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY and its potential for solving systematic problems magnifications of X 6, X 12.5, or X 25. Muscles within the family has been completely unknown. were routinely stained with an aqueous solution In addition, the broader question of the phylo- of potassium iodide and iodine (Bock and Shear, genetic relationships of the Trochilidae with other 1972). Without this stain we probably would not families is still open. A paper by Zusi and Bentz have found or correctly described certain muscles. (1982) and the present paper suggest that com- Zusi made detailed pencil drawings for the figures parative myology has considerable potential for with the aid of a camera lucida. systematic studies at various taxonomic levels. In The species and numbers of specimens dis- discussing relationships of the Trochilidae, pre- sected are: Purple-throated Carib (Eulampis jugu- vious authors have sometimes come to opposite laris), 7; Rufous-breasted Hermit {Glaucis hirsuta), conclusions from similar data. This is partly for 3; Giant Hummingbird (Patagona gigas), 1; Fork- lack of adequate data both for hummingbirds tailed Woodnymph Thalurania jurcata), 2: Violet- and for other families. The future looks more browed Brilliant (Heliodoxa xanthogonys), 2; Try- promising because a comparative myological base rian Metaltail (Metallura tyrianthina), 2; and Ba- for many land bird families is presently emerging hama Woodstar (Calliphlox evelynae), 1. In addi- from the work of various authors. This base con- tion we checked certain points in the Magnificent sists largely of appendicular and jaw myology, Hummingbird (Eugenes fulgens). with which the present descriptions may be com- TERMINOLOGY.—We have followed the pared. "Nomina Anatomica Avium" (Baumel et al., Hummingbirds present a particularly difficult 1979) for terminology of muscles and have usually phylogenetic problem because their locomotor employed anglicized versions of NAA Latin and feeding systems are highly modified for hov- names for other anatomical structures. The NAA ering flight, perching and clinging, and lapping name follows our first use of an anglicized name nectar. These modifications affect virtually all whenever possible. Certain departures from NAA portions of the bird; thus hummingbirds are terminology are explained in the appropriate sec- either unique or highly unusual among birds in tions. many of their structural attributes. For example, Directional terms apply to a bird that is stand- Cohn (1968) argued that those features of wing ing with the head and neck stretched forward myology and osteology in which hummingbirds and the wings fully extended to the side. The resemble only swifts are probably the result of terms "cranial" and "caudal" are used through- convergence from one common aspect of their out except for the skull and hyoid apparatus, in flight—a highly developed powered upstroke of which "rostral" replaces "cranial," and for the the wing. For these reasons we feel that myologi- eye, in which "anterior" and "posterior" are used. cal clues to the phylogeny of hummingbirds will We depart from NAA usage with reference to the be difficult to recognize and that data other than tarsometatarsus, using "caudal" rather than the available jaw, tongue, and wing myologies "ventral" for the plantar surface, and "cranial" might be needed. rather than "dorsal" for the opposite surface. The above comments lead to the third objective Most abbreviations in figures refer to muscles, of this paper. We hope that a demonstration of and we have omitted "M." (for "musculus") to myological variation within hummingbirds and save space. These abbreviations are identified in the identification of those features that are unique Appendix 1. Abbreviations for other anatomical or unusual among birds will stimulate the study features are italicized in the figures and are iden- of functional anatomy and adaptations within tified in Appendix 2. the Trochilidae. ACKNOWLEDGMENTS.—This project was begun METHODS.—Spirit specimens from the collec- during Bentz's tenure as a Smithsonian Postdoc- tions of the National Museum of Natural History, toral Fellow. Partial financial support was re- Smithsonian Institution, were dissected under ceived from Smithsonian Research Award Sg NUMBER 385

3372400 to Zusi, and from Mount Vernon Col- of the eye, just medial to the attachment of M. lege to Bentz. We acknowledge David Steadman rectus dorsalis and lateral to the fleshy attach- for obtaining some of the spirit specimens used in ment of M. quadratus membranae nictitantis. this study. Zusi's pencil drawings were rendered in ink by Carolyn Cox Lyons (Figures \a,b, 2-4, M. OBLIQUUS VENTRALIS (O V) 6-9, lie,), Ellen Paige (Figures \c, 15, 19), and Irene Jewett (the remainder). All illustrations FIGURE la-c were labelled by Ellen Paige. This muscle is the ventral counterpart of M. obliquus dorsalis. Its origin is adjacent and ven- Muscles of the Eye tral to that of dorsalis. The muscle flares out and passes posteroventrolaterally around the eye to Three muscles of the eyelids (M. levator pal- insert on the sclera by a broad, flat aponeurosis pebrae dorsalis, M. depressor palpebrae ventralis, just lateral to the attachment of M. rectus ven- M. tensor periorbitae) that attach on the cranium tralis. are omitted here because we were unable to ob- tain an accurate description by gross dissection. M. RECTUS DORSALIS (R D) However, we include the two intrinsic muscles of the eye associated with the nictitating membrane FIGURE la-c (membrana nictitans) and mentioned in descrip- tions of the extrinsic muscles. This is a broad, strap-like muscle that lies on the dorsomedial surface of the eye. It originates by an aponeurosis from a narrow depression on M. RECTUS MEDIALIS (R M) the posteroventral bony rim of the optic foramen. FIGURE la-c The aponeurosis curves anterodorsally around the optic nerve (nervus opticus) and quickly fans out This muscle arises mainly fleshy from a depres- and gives rise to the fleshy belly. Insertion is by sion in the interorbital septum (septum interor- a broad aponeurosis on the sclera near the dorsal bitale) just anterior to the optic foramen (foramen limit of the eye and lateral to the attachment of opticum) and ventral to the floor of the orbital M. obliquus dorsalis. fonticulus (fonticulus orbitale). The muscle broadens to a strap and passes anteriorly around the medial surface of the eye to insert by a flat M. RECTUS VENTRALIS (R V) aponeurosis on the sclera near the anterior limit FIGURE la-c of the eye. This is the ventral counterpart of rectus dorsalis M. OBLIQUUS DORSALIS (O D) and its aponeurotic origin is continuous with that of dorsalis. It passes anteroventrally around the FIGURE la-c optic nerve and fans out to give rise to the fleshy The origin of this muscle is from a depression belly. Insertion is by a broad aponeurosis on the in the posterior wall of the ectethmoid plate (os sclera medial to the attachment of M. obliquus ectethmoidale) posteromedial to the foramen of ventralis and lateral to the fleshy attachment of the olfactory nerve (foramen orbitonasale medi- M. pyramidalis membranae nictitantis. ale) and ventral to the groove of that nerve (sulcus olfactorius). It is deep to M. rectus medialis. The M. RECTUS LATERALIS (R L) muscle flattens, passes between two rami of the olfactory nerve (nervus olfactorius), and flares out FIGURE la-c as it continues dorsolaterally over the eye to insert This muscle lies on the caudal surface of the by a broad, flat aponeurosis near the dorsal limit eye. It originates mainly fleshy from a depression SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY posterolateral to the origins of rectus dorsalis and accounts are brief and the illustrations lack detail. lateralis, and between the ventral rim of the An important difference between his interpreta- orbital fonticulus and the dorsal edge of M. pro- tion and ours is his recognition of adductor man- tractor pterygoidei et quadrati. The belly passes dibulae externus caudalis as well as adductor laterally around the eye and inserts by a flat mandibulae caudalis in hummingbirds. The for- aponeurosis on the sclera near the posterior limit mer muscle is present in oscine Passeriformes of the eye. (Beecher, 1953; Fiedler, 1951; Richards and Bock, 1973) but absent in swifts (Apodidae) according to Morioka (1974), and the interpretation of the M. QUADRATUS MEMBRANAE NICTITANTIS (Q M N) situation in hummingbirds may therefore have FIGURE \C systematic significance. We found that, as in swifts, the adductor mandibulae caudalis was This broad, flat, fan-shaped muscle lies on the well developed and adductor mandibulae exter- posterodorsomedial surface of the eye from the nus caudalis absent. Moller's description of the optic nerve dorsally almost to the dorsal limit of pterygoideus complex is incomplete and not use- the eye. It has a curved, linear origin that extends ful for comparisons. posteriorly toward the insertion of M. rectus la- teralis, dorsally to the insertion of M. obliquus Fiedler's comments on the jaw muscles of hum- dorsalis, and anteriorly toward M. rectus medi- mingbirds in comparison with those of oscines alis. The fibers pass ventrally and converge on a and other groups are drawn exclusively from tendinous tube that curves around the dorsal half Moller's descriptions. of the optic nerve. This tube transmits the tendon Terminology of the parts of the palatine bone of M. pyramidalis membranae nictitantis. and subdivisions of certain jaw muscles follows that of Richards and Bock (1973).

M. PYRAMIDALIS MEMBRANAE NICTITANTIS (PMN) M. ADDUCTOR MANDIBULAE EXTERNUS (A M E)

FIGURE \C FIGURES 2a-c, 3b,c This is a narrow, fan-shaped muscle that orig- In hummingbirds this muscle consists of two inates ventrally on the eye just medial to the large and well-defined bellies—pars rostralis and insertion of M. rectus ventralis. Its fibers converge pars ventralis. Pars rostralis can be further sub- on a narrow tendon that enters the tendinous divided into temporal, medial, and lateral por- tube of M. quadratus membranae nictitantis an- tions. Pars caudalis of M. adductor mandibulae terior to the optic nerve and passes through the externus, present in many other birds, is appar- tube to emerge on the posterior side of the optic ently absent in hummingbirds. nerve. The tendon then continues ventrolaterally PARS ROSTRALIS (A M E R).—Pars rostralis tem- along the surface of the eye where it passes poralis (A M E R T): This is a large, superficial through a tendinous loop on the sclera before muscle that occupies the temporal fossa (fossa continuing to the anterolateral side of the eye. It temporalis) of the cranium. It originates fleshy attaches on the rostral edge of the nictitating from the entire fossa and from the lateral and membrane. dorsal surfaces of the zygomatic process (processus zygomaticus). Some fibers of rostralis temporalis Muscles of the Jaws originate from a superficial aponeurosis that at- taches along the dorsal edge of the temporal fossa. The only description of the jaw muscles in Insertion is by a tendon that begins as a broad hummingbirds is that of Moller (1931) for the sheet that is parallel to the surface of the cranium. Green-throated Carib {Sericotes holosericeus). His It has a thickened "midrib" that is continuous NUMBER 385 with the main tendon of insertion. In its rostral of the main tendon of rostralis, and continues portion this sheet curves medially into the orbit forward to fan out along the lateral surface of the (orbita) to receive fibers from pars medialis. Fi- mandibular ramus (ramus mandibulae). From its bers from the temporal fossa insert on the medial medial, ventrolateral, and rostrolateral surfaces surface of the broad sheet; those from the super- fibers pass to their insertion on the lateral surface ficial aponeurosis on its lateral surface. The su- of the mandible from the lateral jugomandibular perficial fibers have a weakly pennate arrange- ligament (ligamentum jugomandibulare laterale) ment where they meet at the midrib, but most forward under the orbit and ectethmoid. The assume a fan-like arrangement as they converge jugal bar lies immediately lateral to this muscle. onto the aponeurosis. The aponeurosis emerges The caudal, deep fibers of this muscle from the from the belly of temporalis and is briefly super- medial surface of the zygomatic process insert on ficial as it passes rostroventrally toward its inser- a thin aponeurotic sheet that attaches along the tion. The aponeurosis narrows to form a stout dorsal edge of the mandibular ramus just caudal tendon that is covered laterally by rostralis later- to the tendon of insertion of pars rostralis. A few alis before passing deep to pars ventralis and fibers also attach deep to that tendon. This caudal attaching on the coronoid process (processus co- and deep portion of the muscle lies adjacent and ronoideus) of the mandible (mandibula). lateral to the rostral portion of M. adductor Pars rostralis lateralis (A M E R L): In hum- mandibulae caudalis. mingbirds this is sometimes identifiable as a sep- arate belly but it amounts to little more than a rostral development of the ventral portion of pars temporalis. Fibers arise from the rostrodorsal rim of the ear opening (meatus acusticus externus) Pars caudalis of M. adductor mandibulae ex- and from the lateral surface of the zygomatic ternus is either absent or inextricably fused with process and insert on the ventral and ventrolat- the caudal, deep portion of ventralis just de- eral surfaces of the main tendon of insertion of scribed. We regard it as absent in hummingbirds. pars rostralis just above the point where it is Variations in adductor mandibulae externus crossed by pars ventralis. are chiefly in the relative sizes of its parts and in Pars rostralis medialis (A M E R M): This the configuration of the aponeurotic sheet buried portion is continuous with rostralis temporalis. in pars rostralis temporalis. In Glaucis, pars later- Fibers arise in the orbit between M. pseudotem- alis is scarcely developed and pars ventralis is poralis superficialis and the postorbital process, much reduced, attaching only on the dorsal edge and from the dorsal and medial surfaces of the and dorsolateral surface of the mandibular ra- postorbital process (processus postorbitalis). They mus. The "midrib" of the aponeurotic sheet of insert on both surfaces of the orbital extension of rostralis temporalis is a pronounced, flattened the aponeurotic sheet described under rostralis wall that stands at right angles to the sheet and temporalis. The orbital aponeurosis passes rostro- extends along its caudoventral border. Its free ventrally as a medial extension of the main ten- edge can be seen as a line on the surface of the don of rostralis, narrowing and disappearing as muscle where the fibers meet in pennate fashion. that tendon approaches the coronoid process of In Calliphlox and Patagona the midrib and pars the mandible. lateralis are poorly developed. In Eulampis and PARS VENTRALIS (A M E V).—This major por- Glaucis the narrow, caudodorsal extremity of pars tion of the adductor mandibulae externus arises rostralis temporalis arises in part from the trans- by a strong aponeurosis from the ventral edge verse nuchal crest (crista nuchalis transversa). and tip of the zygomatic process. The aponeurosis Pars lateralis is especially well developed in passes rostroventrally, crosses the lateral surface Metallura. SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY

M. ADDUCTOR MANDIBULAE CAUDALIS (A M C) M. adductor mandibulae caudalis from the or- bital process. Its fibers pass rostroventrally, par- FIGURES 2a,b, 3c allel and adjacent to the superficial fibers of adductor mandibulae caudalis, to their fleshy This stout muscle lies deep to M. adductor attachment on the mandible medial to the coron- mandibulae externus. It extends from the quad- oid process and caudally to the attachments of rate (quadratum) to the mandible. Its origin is from the lateral surfaces of the body of the quad- M. pseudotemporalis superficialis and M. adduc- rate (corpus quadrati) and of the orbital process tor mandibulae caudalis. A few fibers attach on (processus orbitalis quadrati) except for its dorsal the adjacent aponeurotic insertion of M. ptery- edge and lateral surface near the tip, which are goideus dorsalis medialis. occupied by M. pseudotemporalis profundus. The This muscle is not readily separable from M. muscle passes ventrally to its insertion on the adductor mandibulae caudalis. Dorsally the two dorsal surface of the mandibular ramus and on muscles appear to meet at the point of penetra- the medial surface of a superficial aponeurotic tion of a ramus of the mandibular nerve (nervus sheet. Its attachment is immediately rostral to the mandibularis), and ventrally at the tendon of jaw articulation (fossa articularis quadratica), insertion of M. pseudotemporalis superficialis. bounded medially by the attachment of M. pter- Ventrally the two muscles are further demarcated ygoideus dorsalis medialis and rostrally by the by the anterior limit of the superficial aponeurosis two pseudotemporalis muscles. The more super- of insertion of M. adductor mandibulae caudalis. ficial fibers from the body of the quadrate are In Glaucis this muscle is not strongly developed. oriented rostroventrally from origin to insertion; By contrast it is unusually well developed in the deeper fibers from the orbital process are Patagona, and it includes an extensive superficial more vertical in orientation. Criteria for separat- aponeurosis from the dorsal edge of the orbital ing this muscle from M. pseudotemporalis pro- process of the quadrate. fundus are described under that muscle. In Glaucis the more lateral fibers converge on M. PSEUDOTEMPORALIS SUPERFICIALIS (PS S) the lateral surface of an aponeurotic sheet that FIGURES 2b,c, 3b,c inserts along the dorsolateral edge of the mandib- ular ramus caudal to the coronoid process. The This muscle originates on a restricted portion rostromedial fibers insert on the medial surface of of the caudal wall of the orbit above the optic the same aponeurosis and the muscle is thus foramen and between M. protractor pterygoidei unipennate. In Heliodoxa the superficial aponeu- et quadrati and M. adductor mandibulae exter- rotic sheet of insertion is particularly well devel- nus (rostralis temporalis). It extends ventrally, oped. passing between the psuedotemporalis profundus and adductor mandibulae externus (rostralis cau- dalis) to its attachment on a tubercle (tuberculum M. PSEUDOTEMPORALIS PROFUNDUS (PS P) pseudotemporale) of the dorsal surface of the

FIGURES 2b,c, 3c mandibular ramus. The origin includes a par- tially superficial lateral aponeurosis and an inter- This muscle extends from the oribital process nal aponeurosis, each from a pronounced tubercle of the quadrate to the dorsal surface of the man- on the caudal wall of the orbit. Fibers from the dibular ramus. It is partially deep to the insertion cranium and both aponeuroses attach on an apo- of adductor mandibulae externus (rostralis tem- neurotic sheet that is superficial on the caudal poralis). The dorsal attachment occupies the dor- and rostrolateral surfaces of the muscle. This sal edge of the orbital process and a depression in partially investing aponeurosis coalesces to form the lateral surface of the tip of that process. The a stout tendon of insertion. The muscle is multi- muscle overlies the more rostroventral portion of pennate. NUMBER 385

In Glaucis the muscle is more slender and less on most of the ventral and lateral surfaces of the strongly pennate. wall of the palatine trough. In addition, fibers attach on a long, strong aponeurosis that covers most of the ventral surface of the muscle. This M. PROTRACTOR PTERYGOIDEI ET QUADRATI aponeurosis becomes stronger as it passes rostrally (PPQ) to its attachment on the transpalatine process FIGURES 2a-c, 3b and along the prepalatine bar to the ventral surface of the bony shelf that connects the pre- This thick muscle is differentiated into quad- palatine bar with the jugal bar. (See Figure 3a rate and pterygoid portions only at its insertion. for terminology of the palatine and lower jaw.) It lies deep in the orbit between M. pseudotem- The strongest part of this aponeurosis follows the poralis superficialis and M. pterygoideus, pars long axis of the transpalatine process. dorsalis medialis. It originates from the caudal The short fibers of this long muscle pass mainly wall of the orbit and the adjacent portion of the from the mandibular aponeurosis and medial interorbital septum and sphenoidal rostrum (ros- process of the mandible to the dorsal and cau- trum sphenoidale), caudally from the rostral edge doventral surfaces of the palatine aponeurosis; of the ear opening forward to a point just rostral those from the medial surface of the mandibular and ventral to the optic foramen. Fibers of the aponeurosis pass rostromedially to the wall of the quadrate portion attach on a well-marked de- palatine trough. The lateral portion of the pala- pression in the rostromedial surface of the quad- tine aponeurosis is intimately associated with M. rate, including the entire surface of the orbital pterygoideus ventralis lateralis. process and the body of the quadrate rostral to PTERYGOIDEUS, PARS VENTRALIS MEDIALIS, EUS- the otic process (processus oticus quadrati) and TACHIAN SLIP (PT V M E).—This short fleshy slip excepting its ventral portion. Fibers from the departs from the caudomedial surface of the main pterygoid portion insert on the caudodorsal sur- belly of this muscle and passes rostromedially to face of the pterygoid (os pterygoideum) and on attach on the lateral wall of the opening of the an aponeurosis extending forward from a ridge eustachian tube (rima infundibula). on the caudodorsal edge of the pterygoid.

M. PTERYGOIDEUS, PARS VENTRALIS MEDIALIS M. PTERYGOIDEUS, PARS VENTRALIS LATERALIS (PT V M) (PT V L)

FIGURES 2C, 3a-c, bd FIGURES 2C, 3a-c This is a long, powerful muscle that extends This muscle lies lateral to M. pterygoideus from the medial process of the mandible (proces- ventralis medialis and is not clearly separable sus mandibulae medialis) to the palatine (os pal- from it rostrally. Its fleshy caudal attachment is atinum). Its structure is largely unipennate, and on the rostrodorsal edge of the base of the medial partially bipennate. Caudally, fibers have a fleshy process of the mandible and on the adjacent attachment on the rostral edge of the medial caudodorsal surface of the mandibular ramus. Its process of the mandible and on a depression in its attachment lies between that of ventralis medialis ventral surface. The major attachment, however, and that of dorsalis medialis. Fibers pass rostro- is by an aponeurotic sheet that passes caudally medially to their attachment on the caudolateral within the belly of the muscle. It emerges on the portion of the palatine aponeurosis of ventralis dorsal surface of the muscle and immediately medialis. The lateralmost portion of this aponeu- attaches on the tip of the medial process of the rosis, attaching on the transpalatine process and mandible. bony shelf as described under ventralis medialis, The rostral fleshy attachment of the muscle is may in fact represent this muscle. SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY

M. PTERYGOIDEUS, PARS DORSALIS MEDIALIS superficial on the medial surface of the belly. It (PTDM) is folded and stronger from the tympanic process of the exoccipital (ala tympanica, os exoccipitale). FIGURES 2C, 3b,c The much smaller aponeurosis from the crest is This broad, strap-like muscle lies in the orbit internal. between the other portions of the pterygoideus The more superficial fibers insert on the medial muscle and the protractor pterygoidei et quad- surface of a large, superficial aponeurosis that rati. From its attachment on the ventral and attaches along a poorly defined transverse crest lateral surfaces of the pterygoid, the adjacent wall on the ventral and ventrolateral surfaces of the of the palatine trough, and the caudal part of the mandible. Deeper fibers attach just caudal to that palatine hasp, it passes caudoventrolaterally over aponeurosis on the caudodorsal slope of the ven- M. pterygoideus, pars ventralis medialis and pars tral surface of the mandible, on a deep aponeu- dorsalis lateralis to its insertion on the dorsome- rosis that inserts on the tip of the retroarticular dial surface of the mandibular ramus immedi- process (processus retroarticularis), and along the ately rostral to the articulation. Fibers also attach adjacent caudal edge of the mandibular ramus to on a short aponeurotic sheet that outlines its a point just medial to the retroarticular process. fleshy attachment. This aponeurosis is especially This aponeurosis extensively overlaps the aponeu- well developed along the rostral edge of the mus- rosis of origin from the edge of the ear opening, cle. and these aponeuroses coalesce at their medial The mandibular attachment is particularly limit to form the occipitomandibular ligament broad in Glaucis, extending forward to a point (ligamentum occipitomandibulare). This liga- just medial to the coronoid process of the man- ment extends from the tympanic process of the dible. The muscle is somewhat differentiated into exoccipital to the caudal border of the mandible rostral and caudal parts, the latter attaching on medial to the retroarticular process and caudal to the ventral surface of the lateral portion of the the attachment of the medial jugomandibular pterygoid where it is partially overlapped by the ligament (ligamentum jugomandibulare medi- caudal edge of the rostral part. ale).

M. DEPRESSOR MANDIBULAE (D M) Muscles of the Tongue and Hyoid Apparatus

FIGURES 2a, 3a, bd The most important descriptive works on myol- This is a stout muscle that passes from the ogy of the hyoid apparatus (apparatus hyobran- ventrolateral surface of the cranium to the caudal chialis) and tongue of hummingbirds are those of end of the lower jaw and lies just behind the ear Moller (1931) for Sericotes holosericeus, and Wey- opening. Area for fiber attachment is greatly mouth et al. (1964) for Eugenes fulgens. Moller's increased in this muscle by the presence of exten- work included brief descriptions and crude illus- sive external and internal aponeuroses. The origin trations of some muscles, but he overlooked three of the more superficial portion of this muscle is muscles and incorrectly described another. Wey- from a well-defined inflated portion of the cran- mouth et al. overlooked one muscle and gave ium caudal to the ear opening and along the inaccurate or incomplete descriptions of two oth- adjacent transverse nuchal crest. Origin of the ers. Other workers have alluded to the extraor- deeper portion is from aponeurotic sheets that dinarily long hyoid horns (cornu branchiale) and extend from the caudal edge of the ear opening their associated muscles. and from a crest just caudal to that edge. The We did not study the tracheal or laryngeal aponeurosis from the edge of the ear opening is muscles in detail, but we note that none has an NUMBER 385 attachment on the hyoid apparatus in humming- of the mandible" and "apparently, on the belly birds. of M. stylohyoideus."

M. INTERMANDIBULARIS (IM) M. SERPIHYOIDEUS (SE) FIGURE \a,b FIGURES 2a, 4a,i This thin sheet of muscle is slung between the This thin, strap-like muscle lies on the floor of mandibular rami. It consists of two separate por- the throat just caudal to M. intermandibularis. It tions: a rostral sheet that has a linear origin along has a linear origin along the transverse nuchal the dorsomedial surface of the ramus from a point crest bordering M. depressor mandibulae. Here about halfway between the origin of M. bran- it lies deep to M. cucullaris capitis. The muscle chiomandibularis to the mandibular fenestra (fe- passes ventrally along the surface of the mandib- nestra mandibulae), and a more caudal sheet ular depressor, angles rostromedially over M. sty- under the base of the tongue that originates on lohyoideus, and emerges below M. branchioman- the dorsal surface of the ramus caudad from the dibularis. The muscle is crossed obliquely by a mandibular fenestra for about 3 mm. The muscle tendinous intersection that follows the medial lies dorsal to M. branchiomandibularis but ven- border of M. stylohyoideus. The belly inserts near tral to the larynx and floor of the mouth. Fibers the midventral portion of a transverse tendinous of both sheets meet along a midline raphe; those sling that supports the hyoid apparatus and per- of the anterior sheet angle rostromedially toward mits it to move forward or backward beneath the the raphe, and those of the caudal sheet angle larynx. The sling originates on the ventrolateral caudomedially. The caudal end of the muscle is surface of the larynx, passes ventrally lateral to extended by a weak sheet of connective tissue the ceratobranchiale (os ceratobranchiale), and that sends an arm caudolaterally on either side to curves ventromedially between the stylohyoideus the lateral fibers of M. serpihyoideus. and branchiomandibularis muscles to meet its The two sheets that comprise this muscle are opposite half in the midline. In some specimens sometimes formed of an irregular series of flat the lateralmost fibers attach on an arm of the straps that may lie at different angles, causing weak connective tissue sheet that forms the caudal gaps or overlaps between them. The larger gap limit of M. intermandibularis. between the two sheets may contain one or several The above description applies to Eulampis and such straps. Glaucis. In the remaining forms (Thalurania, Cal- In Heliodoxa, Thalurania, and Calliphlox the mus- liphlox, Heliodoxa, Metallura, and Patagona) the lat- cle is divided as in Eulampis, but in Glaucis it is eral portion of this muscle meets its opposite continuous and cannot be divided into rostral member on a median raphe that is shared by M. and caudal portions. In Metallura the muscle is intermandibularis. The medial portion separates divided only by a narrow gap and in Patagona by from the lateral portion and passes dorsal to it to a narrow gap only at the origin but not on the insert on a connective tissue sling as described for raphe. We found the muscle to be divided in Eulampis. This sling lies deep to the rostral part of Eugenes; apparently Weymouth et al. overlooked the muscle (Figure 4b) and to the caudal portion the rostral portion. of M. intermandibularis. The muscle is partially divided by a tendinous intersection that is asso- M. GENIOGLOSSUS (GG) ciated with the lateral portion. FIGURE 4a Moller (1931) overlooked this muscle. Wey- mouth et al. (1964:254) inaccurately described it This is a long, slender, strap-like muscle that, as attaching on "the ventral margin of the angle with its twin, extends along the midline of the 10 SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY floor of the mouth dorsal to M. intermandibu- In Patagona the origin is on the dorsal surface laris. It originates from the caudomedial edge of of the upper jaw at the level of the caudal end of the mandibular symphysis (symphysis mandibu- the nares (apertura nasalis ossea), and in Heliodoxa laris) and passes caudally. When the tongue is in just rostral to the craniofacial hinge. In Metallura its normal resting position the basihyale lies in a the insertion is by a short, flat aponeurosis. sheath-like evagination of the floor of the mouth. The fibers of this muscle pass caudad and termi- M. BRANCHIOMANDIBULARIS (BM) nate on the mouth lining at the base of this sheath. There is no insertion on the hyoid appa- FIGURES 2a, 4a,c ratus or tongue. In some specimens lateral fibers This is a long, strong, strap-like muscle that lies of this muscle curve laterally and attach on the along the mandibular ramus ventral to M. inter- mouth lining near the rostrolateral portion of the mandibularis and the large sublingual salivary larynx. gland (glandula mandibulares caudale), and In Heliodoxa all fibers curve laterally; no fibers crosses over M. stylohyoideus to engulf the epi- insert along the midline. branchiale along its entire length. The 4 mm Weymouth et al. (1964) and Moller (1931) origin is fleshy from the medial surface of the overlooked this muscle. ventral half of the ramus about midway between the mandibular fenestra and the tip of the man- M. STYLOHYOIDEUS (ST) dibular symphysis (symphysis mandibularis). The muscle passes caudally, and at the junction of the FIGURES 2a, 4a,cf ceratobranchiale and epibranchiale it developes This is a long, strap-like muscle that follows a dorsomedial trough into which the epibranchi- the epibranchiale (os epibranchiale) and bran- ale disappears. This muscle then ensheaths the chiomandibularis muscle in its course. It arises epibranchiale. Fibers from either side of the along the transverse rostral edge of a depression trough curve dorsally around the epibranchiale in the roof of the skull just behind the craniofacial and merge as they pass distally in parallel ar- hinge (zona elastica cranifacialis). It extends rangement toward its tip. The muscle covers both backward, following the curve of the cranium sides and the deep surface of the epibranchiale, and closely appressed to the lateral edge of M. but superficially the belly is separated by a nar- branchiomandibularis. The epibranchiale and row gap that is closed by a tough membrane these muscles occupy a shallow trough lateral to through which the epibranchiale may be seen. the cerebellar prominence (prominentia cerebel- Toward the distal tip the gap closes and the laris). The muscle continues rostrad below the epibranchiale becomes completely ensheathed by cranium and mandibular ramus. It crosses M. the belly. The long fibers extend almost the full serpihyoideus ventrally and angles anteromedi- length of the muscle belly and attach on a con- ally parallel to that muscle across M. branchio- nective tissue sheath that contains the distal end mandibularis, to pass through the lateral portion of the epibranchiale. of the connective tissue sling associated with M. In Heliodoxa the two epibranchiales and this serpihyoideus. It continues rostrad ventral to M. muscle curve to the right of the dorsal bar of the interceratobranchialis and M. ceratoglossus to its upper jaw, pass over the bony flanges of the nares, insertion in a longitudinal depression on the dor- and then curve left between the dorsal and ven- solateral surface of the basibranchiale rostrale, tral bars to enter a sheath in the roof of the upper somewhat caudal to its midpoint. The insertion jaw. In Glaucis the two muscles extend rostrad on is along the dorsal edge of M. hypoglossus obli- either side of the dorsal bar of the upper jaw and quus. The muscle is fleshy throughout. terminate over the nasal flanges. NUMBER 385 11

M. INTERCERATOBRANCHIALIS (ICB) face of the basibranchiale opposite the caudal end of the entoglossum. Fibers pass dorsocaudally FIGURE id,f,g to insert on the caudal cartilagenous extension of This spindle-like muscle lies along the medial the entoglossum. This slip lies lateral to the ros- surface of the ceratobranchiale. It originates from tralmost portion of the main belly. the medial surface of all but the rostralmost Weymouth et al. (1964) described a lesser ex- portion of that bone, and inserts in part fleshy on tent of origin and did not mention the fan-shaped the lateral edge of the basibranchiale caudale (os structure or the separate rostral slip in Eugenes. basibranchiale caudale), and in part by a long, superficial, medial aponeurosis that attaches on M. HYPOGLOSSUS ROSTRALIS (HG R) the tip of the basibranchiale caudale. The muscle is thus unipennate. FIGURE 4e-g This is a tiny muscle arising from the lateral, M. CERATOGLOSSUS (CG) ventral, and medial surfaces of the entoglossum just rostral to the insertion of M. hypoglossus FIGURE $d-g obliquus. The short belly narrows as it extends This slightly fan-shaped muscle lies along the rostrad ventral to the entoglossum to insert by a ceratobranchiale and basibranchiale lateral to M. flat tendon on the ventral portion of the rostral hypoglossus obliquus and medial to M. stylo- cartilagenous extension of that bone. The origin hyoideus and M. branchiomandibularis. It arises of this muscle is somewhat divided by the ento- by two heads, a long, slender, caudal one from glossum such that the muscle has been described the caudolateral surface of the ceratobranchiale, as having lateral and medial heads (Weymouth and a stouter rostral one from the rostrolateral et al., 1964). surface of that bone. The bellies fuse and narrow as the muscle proceeds rostrad to form a tendon Muscles of the Vertebral Column that inserts on the ventral edge of the entoglossum In Eulampis there are 14 cervical vertebrae (ver- just rostral to its articulation with the basibran- tebrae cervicales) and three unfused thoracic ver- chiale. tebrae (vertebrae thoraciae). Vertebrae are num- bered in sequence starting with the atlas. Verte- M. HYPOGLOSSUS OBLIQUUS (HG O) bra 13 may bear a tiny rib (costa) and vertebra 14 bears a well-developed floating rib. The cer- FIGURE 4d-g vical vertebrae are morphologically and function- This spindle-shaped muscle lies along the bas- ally grouped into three sections (Figure 6). In ibranchiale rostrale (os basibranchiale rostrale) hummingbirds the first section includes vertebrae where it is bounded laterally by M. ceratoglossus. 1 through 4; the second section, 5 through 10; It originates along the entire basibranchiale, cau- and the third section, 11 through 14. The func- dally from the lateral surface and rostrally from tional and morphological properties of these sec- the ventral surface. The insertion is on the caudal tions in birds are described by Boas (1929) and extension of the entoglossum at a level caudal to Zusi (1962). Muscles of the free thoracic vertebrae the articular surface of that bone. The muscle has also attach on the fused vertebrae of the synsa- a skewed, fan-like shape because of its long origin crum that form the cranial portion of the pelvic and restricted rostral insertion. It is fleshy girdle in hummingbirds. throughout. The following synonymy for parts of vertebrae A separate, small, fan-shaped slip originates may prove useful; our terms, anglicized from from the rostroventral portion of the lateral sur- Baumel et al. (1979), are in the left column. 12 SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY

vertebral body centrum closely appressed to the aponeurosis of M. longus vertebral arch neural arch colli dorsalis, pars caudalis. At the level of verte- spinous process neural spine bra 11, the tendon gives way to a fleshy, parallel- ventral process hypapophysis fibered belly. Dorsal to vertebra 7 this belly ends caudal articular process postzygapophysis dorsal process anapophysis on a narrow tendon that continues cranially carotid process sublateral process alongside the mid-dorsal line. A second belly originates from the tendon at the caudal end of We use the term "dorsal process" with reference vertebra 3 and inserts on the cranium just below to the caudal articular process, and "spinous proc- the transverse nuchal crest, between the insertions ess" rather than "dorsal process" for the median, of M. complexus and M. splenius capitis. vertical process of certain vertebrae (see Baumel The tendon of origin in Metallura is from ver- et al., 1979:64, 65). The costal process (processus tebra 14. In Glaucis, Thalurania, Patagona, Heliodoxa, costalis) of the cervical vertebrae consists of two Metallura, and Calliphlox it comes from 13. major portions that we call the head of the costal process and the costal spine (Figure 7c). Most muscles of the vertebral column have not M. SPLENIUS CAPITIS (S CA) been described previously for hummingbirds. Burton (1971) noted and compared the remark- FIGURE 5b,c able cruciform structure of M. splenius capitis in This muscle originates by several short, flat hummingbirds, swifts, and a few other families. tendons from the caudodorsal border and dorsal process of the axis. As pointed out by Burton M. COMPLEXUS (C) (1971), the right and left muscles have an inter-

FIGURE 5a,b digitating or cruciform pattern of origin in hum- mingbirds and some other families. The muscle This strap-like, superficial muscle originates by inserting on either side of the midline originates two slips from the transverse processes (processus from the opposite side of the midline. In Eulampis transversus) of vertebrae 4 and 5. The slips merge there are 6 or 7 overlapping layers of flat tendons as the belly passes craniodorsally to its insertion of origin, mostly from the dorsal processes. Only on the transverse nuchal crest from near the the deepest pair originates from the middle por- median line laterally to the upper limit of M. tion of the ridge between the dorsal processes. depressor mandibulae. The insertion is immedi- From these short tendons each of the fleshy slips ately dorsal to that of M. biventer cervicis. The fans out and fuses with other slips before inserting belly contains three tendinous intersections that on the dorsal and lateral portions of the occipital pass craniomedially from its lateral edge without region. The right and left bellies are more or less reaching the medial border. The medial fibers divisible into two portions, a thinner dorsal one thus extend uninterrupted for the length of the and a thicker lateral one. The thicker portion is belly, while the lateral ones are divided into four formed from both superficial and deep slips; the segments. thinner portion arises only from intermediate ten- In Metallura the origin is from vertebrae 4, 5, dons. The dorsal portion has a roughly linear and 6. insertion deep to those of M. complexus and M. biventer cervicis. The lateral portion inserts on a M. BIVENTER CERVICIS (B C) broader area medial to M. rectus capitis lateralis.

FIGURE 5a,b In one specimen slips inserting on the right side originated in part by a slender tendon from the This muscle is long and slender, extending from left dorsal process of the atlas, and another from the 14th vertebra to the cranium. It originates by the dorsal process of vertebra 3. The latter tendon a flat tendon from the spinous processes of verte- passed forward toward dorsal process 2 before brae 13 and 14. The tendon passes cranially, penetrating the left belly of M. longus colli dor- NUMBER 385 13

salis and turning toward the right side. M. FLEXOR COLLI LATERALIS (F C L)

FIGURE 5a, c-e M. RECTUS CAPITIS LATERALIS (R C L) In hummingbirds this muscle lies largely cau- FIGURE ba-d dal to M. rectus capitis dorsalis rather than deep This strap-like muscle of the cranial portion of to it as in many other birds. It originates from the neck lies lateral to M. rectus capitis ventralis the transverse processes of vertebrae 3, 4, and 5, and to the carotid artery (arteria carotis interna), and some fibers attach between the transverse and ventral to M. complexus. The muscle arises processes on the lateral surface of Mm. intertrans- by three short tendons, the most caudal coming versarii. The main, superficial portion of the belly from the tendon of M. longus colli ventralis just proceeds cranioventrally and inserts by a short caudal to the level of the ventral process of ver- tendon on the lateral projection of the ventral tebra 3, and the other two from the ventral process of the atlas. Deeper fibers of this muscle processes of vertebrae 3 and 2 respectively. Fleshy insert by a short tendon on the lateral projection slips from these tendons fuse and continue to an just dorsal to the attachment of the main tendon insertion that is partly aponeurotic and partly of M. longus colli ventralis. The smallest slip fleshly, along the lateral portion of the transverse arises from the transverse process of vertebra 3 nuchal crest just caudal to M. depressor mandi- and inserts on the atlas. Its fibers attach on the bulae. inner surface of the tendon of insertion of the In Patagona the slip from 2 is relatively small main portion and on the adjacent bony surface and the caudal portion from M. longus colli of the atlas. ventralis relatively large. The slip from 2 is absent M. RECTUS CAPITIS VENTRALIS (R C V) in Heliodoxa and Metallura. FIGURES 3a, ba,c,d M. RECTUS CAPITIS DORSALIS (R C D) This stout muscle lies ventrally on the neck

FIGURES 3a, bc-e between the branches of the carotid artery as they emerge from the neck and enter the skull. It arises This muscle is deep to M. complexus, M. rectus from the caudoventral surface of the body (corpus capitis lateralis, and M. rectus capitis ventralis. It vertebrae) of vertebra 4, the ventral processes of consists of three slips that extend from origins on 3, 2, and 1, and from aponeuroses extending the dorsal processes of the caudolateral portion of forward from these ventral processes. Fibers from the vertebral arch (arcus vertebra) of vertebrae 1, vertebrae 1 and 2 fan out cranially to insert fleshy 2, and 3 to the caudal transverse crest of the on the basitemporal plate of the cranium, basitemporal plate (lamina basitemporalis), from bounded by the eustachian tube, the rostral edge the midpoint laterally almost to the ear opening, of the basitemporal plate, the ear openings, and and from the area immediately behind the crest. the caudal transverse crest of the basitemporal The middle belly is largest and it has a tendinous plate. The slips from different vertebrae are par- insertion on the middle and lateral portions of tially separable at their origins, but they quickly the caudal transverse crest. The small anterior form a compact muscle mass. The muscle in some belly inserts deep and caudal to the insertion of specimens is weakly divided by one or two trans- the second slip. The caudal belly is long and verse, tendinous intersections. spindle-shaped. Some of its deeper fibers arise from the lateral surface of the transverse process MM. INTERCRISTALES (IC) of 3. It inserts mainly by a long, superficial apo- FIGURES 5b,c,e, 7a,e neurosis on the medial portion of the transverse crest and in part by fleshy fibers adjacent to the This series of bellies lies deep to M. longus colli aponeurosis. dorsalis and connects successive vertebrae from 14 SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY the craniodorsal portion of the vertebral arch to In Glaucis and Patagona only bellies four and the caudodorsal portion of the arch of the next five (from the front) are displaced laterally from cranial vertebra. The origin and insertion of suc- the midline by slips of M. longus colli dorsalis, cessive bellies on a given vertebra are separated pars cranialis. by the transverse-oblique crest (crista transverso- obliqua). In the second neck section they originate M. LONGUS COLLI VENTRALIS (L C V) along the lateral edge of the transverse-oblique crest and pass forward to insert on a depression FIGURES 5a, c-e, 6a,b, lb,d of the vertebral arch between the transverse- This large muscle occupies most of the ventral oblique crest and the midline. The bellies are surface of the neck and is bordered above by the differently developed in different portions of the Mm. intertransversarii and Mm. inclusi. It con- neck, as are the transverse-oblique crests. Differ- sists of a series of compound slips inserting on the ences are essentially as follows (numbers refer to costal spines of vertebrae 2 through 12. Origins vertebrae). are fleshy or semitendinous from the carotid proc- 1-2: From cranial face of vertebral arch 2 esses or ventral processes of 4-18. The first slip below transverse crest, fibers converge on dorsal attaches on the costal spine of the axis by a long, process 1. strong tendon that receives fleshy fasciculi on its 2-3: Belly broad and thick, covering most of ventral surface from the carotid processes of ver- vertebral arch. Medial fibers oriented longitudi- tebrae 4 through 9 and the ventral processes of nally and somewhat separate from more lateral vertebrae 10 through 12. The next four slips ones that angle craniolaterally from origin to consist of long slender tendons, each lying dorsal insertion. Lateralmost fibers pass directly be- to the preceding one, that receive fasciculi ante- tween dorsal processes of 3 and 2. Connects cau- riorly from the carotid process of the second dal edge, dorsal surface of vertebral arch, and vertebra back, and caudally from the ventral dorsal process of 3, to caudal edge of vertebral processes of neck section 3 and the thoracic ver- arch and dorsal process of 2. tebra as shown in Figure 6. Slips inserting on 3-4: Smaller than above. Lateral portion less vertebrae 7 through 12 receive fasciculi from the developed, and caudal attachment narrower be- second vertebra caudally and from varying num- cause of medial shift of dorsal process. This and bers of successive vertebrae. The tendon to ver- all succeeding bellies deep to M. cervicalis ascen- tebra 8 is relatively broad, receiving a stout fas- dens in lateral view. ciculus from 10 on its medial portion and the 4-5: Much smaller, long, and slender. Origin more slender and caudal fasciculi on its lateral and insertion as described above for second neck portion. The short fasciculi originating on the section. This and next three bellies displaced second vertebra caudal to that of insertion that laterally from midline of vertebral arch. are associated with each slip of this muscle are 5-6: Similar to above but slightly broader. broad and flat as they pass forward along the 6-7: Similar to 5-6. intervening vertebra. At the cranial end of that 7-8: Broader than 6-7. vertebra they give way to a flat tendon that fuses 8-9: In 9, transverse-oblique crest much less with the longer tendon of insertion of the slip. prominent and abruptly shifted caudad. Muscle broad and flat, bordering midline of vertebral arch. M. FLEXOR COLLI MEDIALIS (F C M) 9-10, 10-11, 11-12, 12-13, 13-14: Bellies flat FIGURE 5d,e and border midline as above, but become pro- gressively narrower so that last belly is small. This muscle lies deep on the ventral side of the Originate on cranial slope of vertebral arch and cranial portion of the neck where it is closely insert on caudal slope of adjacent vertebral arch. associated with M. longus colli ventralis. Its slips NUMBER 385 15

extend forward from the carotid processes to the cle mass is a compact unit, and the aponeuroses caudal and lateral surfaces of the ventral proc- of origin from vertebrae 12, 13, and 14 partially esses. Slips originate by short tendons from ver- fuse into a broad sheet. Fibers from a particular tebrae 6 and 5 and insert on 3. Slips from 5 and vertebra of insertion pass back to their origin on 4 insert on 2. this sheet, and the origin of a given slip may be broad enough to include aponeurotic attach- ments from several vertebrae. Bellies inserting on M. LONGUS COLLI DORSALIS, PARS CRANIALIS the dorsal processes were traced back to the fol- (LCD CR) lowing pattern of origins from the dorsal edges of FIGURES 5b, la the spinous processes (numbers refer to verte- brae) : This muscle of the craniodorsal surface of the neck consists of four slips that lie immediately insertion origin dorsal to Mm. intercristales. The muscle origi- 2 11, 12, 13, 14 nates from the dorsomedial surface of the verte- 6 11, 12 bral arch of the vertebrae 6, 5, 4, and 3. The slips 7 11, 12, 13, 14 8 12, 13, 14 pass cranially to attach in sequence on the ventral 11, 9 12, 13, 14 surface of the tendon of insertion of pars caudalis. 10 12, 13, 14 The slip from vertebra 6 is very thin and lies 11 13, 14, 15 mostly deep to pars caudalis. The slips from 5 12 14, 15, 16 and 4 are relatively stout. The lateral portion of 13 15, 16, 17, 18 the slip from 4 passes forward deep to the slip 14 15, 16, 17, 18 from 5 and inserts just cranial to the attachment The first slip is long and strong, giving way of that slip. The slip from 3 consists of only a few cranially to a strong tendon to dorsal process 2. deep fibers. This tendon is shared by pars cranialis. Insertion In one specimen the medial fibers from verte- of the second and narrowest slip is by a short bra 4 gave rise to a slender tendon that passed tendon on the dorsal process of 6. The remaining over the axis, the cranialmost belly of Mm. inter- slips are broader and occupy the medial surface cristales, and the tendon of M. splenius capitis, to of aponeuroses from the dorsal processes of 7 insert on the dorsal process of the atlas. through 14 that are occupied on their lateral The pattern of slips in Patagona resembles that surface by M. cervicalis ascendens. of Eulampis. In Heliodoxa an additional slip arises from vertebra 7, and in Thalurania, Metallura, and M. CERVICALIS ASCENDENS (C A) Calliphlox extra slips arise from 7 and 8. There was no slip to the atlas in Heliodoxa, Metallura, and FIGURES 5a,c,e, la,b,e, 8a Calliphlox. This muscle consists of a series of bellies lying along the dorsolateral surface of the neck between M. LONGUS COLLI DORSALIS, PARS CAUDALIS M. longus colli dorsalis and Mm. intertransver- (LCD CA) sarii. In general, each belly inserting on the dorsal process of one vertebra receives slips from the FIGURES 5a,b, la transverse processes of the second and third ver- This is the major dorsal muscle of the neck and tebrae caudal to that of insertion. Origins are is continuous with pars thoracica from the tho- partly tendinous and partly fleshy. The longer of racic vertebrae and synsacrum. We define pars the two slips of each belly lies caudal and dorsal caudalis as those slips inserting on vertebra 14 to the shorter slip. Both slips converge cranially and forward. Separation of slips at their origin is onto an aponeurosis that inserts on the dorsal necessarily somewhat artificial because the mus- process. This aponeurosis serves primarily the 16 SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY longer slip; the shorter has a more fleshy insertion In the first neck section, the belly between on the caudal articular process ventral and lateral vertebrae 4 and 5 is similar to those of the second to the aponeurosis. Caudally (vertebrae 9 and 10) section but the aponeuroses are weaker and the the dorsal surface of the tendon of insertion is muscle blends more with Mm. inclusi. The belly largely occupied by M. longus colli dorsalis pars between vertebrae 3 and 4 is much reduced, with caudalis, whereas the ventral surface receives the weak aponeuroses. Fibers pass forward from the longer slip of this muscle. Vertebra 9 receives a transverse process to occupy the concavity medial third slender slip from 13. to the costal process of vertebra 3. The first belly We regard this muscle as those bellies inserting is small. It arises fleshy from the head of the costal on vertebrae 3 through 13. The slip to 13 consists process of vertebra 3 and passes to the lateral of fasciculi from 15 and 16 and fibers from the surface of the vertebral arch of the axis. It lies ventral surface of a superficial aponeurosis from mostly deep to the cranialmost slip of M. flexor the edges of the craniodorsal synsacral depression. colli lateralis. Several longer slips occur in the The entire belly is closely associated with M. cranial portion of this muscle. From the cranio- longus colli dorsalis and is continuous with M. ventral portion of the costal processes of 6 and 5, thoracicus ascendens. slips extend forward to a semitendinous insertion on the dorsal edge of the costal spine of vertebra MM. INTERTRANSVERSARIl (IT) 3. Dorsal to this slip, another extends from the FIGURES ba,e, 7b,d,e, 8a cranial portion of the costal process of 6 to a long This series of multipennate bellies lies along aponeurosis attaching on the transverse process of the lateral surface of the neck between M. longus 4, dorsal to the costal spine. colli dorsalis and M. longus colli ventralis. Each In section three, the belly between vertebrae 10 belly extends from the transverse process and and 11 is well developed. Its major aponeurosis costal process of one vertebra to the transverse extends superficially from transverse process 10 process and costal process of the next cranial caudally and sends fibers in a fan-shaped pattern vertebra. Its structure differs somewhat in differ- to the transverse process of 11 and to its cranially ent sections of the neck. This muscle is intimately directed aponeuroses. A strong ventral aponeu- associated with Mm. inclusi. rosis from the costal process of 11 extends cra- In a typical belly of the second neck section— nially and sends fibers to the transverse process for example, that between vertebrae 6 and 7—a and body of vertebra 10 (the latter portion rep- long aponeurosis from transverse process 6 ex- resents Mm. inclusi). Between vertebrae 11 and tends caudally almost to transverse process 7 and 12 the belly is slightly narrower, being displaced it receives pennate fibers on its lateral surface ventrally somewhat by the larger bellies of M. from a smaller aponeurosis that passes cranially longus colli ventralis. Between vertebrae 12 and from transverse process 7. Fibers from the medial 13, 13 and 14, and 14 and 15 the bellies are surface of the larger aponeurosis extend caudally markedly reduced in keeping with the sharp re- and sometimes medially to attach on the lateral duction in the lateral surface of the transverse surface of the major aponeurosis of Mm. inclusi process and the absence of the costal process in dorsalis and on the transverse process of 7. Ven- vertebrae 13, 14, and 15, which bear ribs. trally, fibers extend forward from the anterior This muscle is continued caudally as M. ilio- face of the head of the costal process of 7 to the costalis. lateral surface of the costal process of 6 and to the concavity between the costal process and MM. INCLUSI (IN) body of vertebra 6. Superficially, some fibers FIGURE Ic-e extend from a given vertebra to the second ver- These muscles lie on the lateral surfaces of the tebra cranial or caudal to it. vertebrae deep to Mm. intertransversarii. They NUMBER 385 17

begin on vertebra 3, end on 10, and are best M. ILIOCOSTALIS (ILC) developed in the second neck section. Each typi- FIGURE 8a cal belly is divided into three slips, one lying dorsal and one ventral to the vertebral artery This series of slips appears to be a modified (arteria vertebralis), and a thin, superficial, dorsal continuation of Mm. intertransversarii. The bel- slip that is described under this muscle although lies between vertebrae 16 and 15, and 17 and 16 it may represent an aberrant slip of Mm. inter- interconnect the lateral portions of the transverse transversarii. The fibers from each of these slips processes. The caudalmost belly arises from the have a broad fleshy attachment on a given ver- craniolateral portion of the synsacrum (fused tebra and converge onto a large aponeurosis that transverse process of 18) and inserts on the lateral originates on the next caudal costal process. portion of transverse process 17 and the adjacent The dorsalmost slip inserts along a dorsolateral dorsocaudal edge of the associated rib. In addi- ridge of the vertebral arch that begins as a pro- tion to these bellies, a larger, longer slip arises tuberance near the midpoint of the side of the along a long aponeurosis from a short spine on arch and continues caudally along the caudal the craniolateral tip of the synsacrum and inserts articular process. Fibers extend caudolaterally on the transverse processes of vertebrae 17, 16, and converge onto the ventral surface of a broad and 15 dorsomedial to the smaller bellies. The but weak aponeurosis that originates on the dorsal long aponeurosis of this portion is shared by M. edge of the next caudal transverse process. A few thoracicus ascendens. fibers of the craniolateral portion of the slip at-

tach on a thin aponeurosis from the protuberance "M. LONGISSIMUS DORSl" of the vertebral arch. This aponeurosis curves craniolaterally to the dorsolateral tip of the trans- M. longus colli dorsalis thoracica and M. thor- verse process of the same vertebra. Between the acicus ascendens form a complex muscle mass aponeurosis and the caudal border of the preced- which, in whole or in part, is sometimes referred ing caudal articular process, a "window" reveals to as the longissimus dorsi. Our interpretation of the deeper portion of Mm. inclusi (Figure le). these muscles is based on the premise that they The large middle slip attaches on the entire should be interpreted as continuations of neck lateral surface of the vertebral arch deep to the muscles, barring evidence to the contrary; in so dorsal slip. Its fibers converge on the medial doing we conclude that a separate "longissimus surface of a large, strong, fan-shaped aponeurosis dorsi" is superfluous in describing hummingbirds. that attaches along the craniolateral edge of the The basic structure of the thoracic muscle mass next caudal costal process. is best visualized in terms of its aponeurotic The ventral slip is similar in structure, but framework because the slips of these muscles are arises from the ventrolateral surface of the verte- compacted and often inseparable. A series of bral body and converges on an aponeurosis that superficial aponeuroses extends craniolaterad attaches on the craniolateral edge of the costal from the dorsal edge of the spinous processes of process between its head and the carotid process. the thoracic vertebrae. These are clearly contin- The belly between vertebrae 4 and 5 has well- uations of those of M. longus colli dorsalis, pars developed aponeuroses, but that between 3 and caudalis. A deeper series of shorter aponeuroses 4 is much reduced, largely fleshy, and fused with from the dorsolateral surface of the thoracic spi- the belly of Mm. intertransversarii. The belly nous processes parallels the first series; we assign between vertebrae 9 and 10 is much reduced, and both series to M. longus colli dorsalis thoracica, the last belly, from 11 to 10, is restricted to a although it is possible that the deep series repre- small ventral slip arising from an aponeurosis sents a modification of Mm. intercristales. Lying common to Mm. intertransversarii. between these two series is a set of long, broad 18 SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY aponeuroses that pass caudolaterad from the dor- neck, these aponeuroses are shared by the ascen- socaudal tip of the spinous processes of the tho- dens muscles. racic vertebrae and vertebra 14. This series was Fibers of the deep portion arise from the lateral assigned to M. longus colli dorsalis thoracica by surfaces of the thoracic spinous processes, and Boas (1929, pi. 15: fig. 7) but we regard it as a from a deeper series of aponeuroses that pass thoracic specialization of M. thoracicus ascendens craniad from the caudodorsal portion of the lat- because of its lateral origins and medial insertions. eral surface of the spinous processes of vertebrae These aponeuroses may have originated as a dor- 16 and 17 and of the first synsacral vertebra. somedial extension of the typical aponeuroses of Fibers pass craniad to their insertions on the that muscle, which extend caudad from the cau- spinous processes, on the medial surfaces of the dal articular processes of the thoracic vertebrae aponeuroses of insertion of M. thoracicus ascen- and are clearly a continuation of those shared by dens to the spinous processes, and on the caudal M. longus colli dorsalis and M. cervicalis ascen- articular processes and their associated aponeu- dens in the neck. Aponeuroses passing craniad roses. from the craniolateral portion of the synsacrum and the transverse processes are associated pri- M. THORACICUS ASCENDENS (T AS) marily with M. iliocostalis, which probably rep- resents a modification of Mm. intertransversarii. FIGURE 8a A broad, superficial aponeurosis from the edges of the synsacral depression passes craniad and This large muscle mass originates from the covers much of the thoracic muscle mass. This dorsal surfaces of the transverse processes of the aponeurosis serves as partial origin for M. thora- thoracic vertebrae and from the surface of the cicus ascendens as we interpret that muscle. synsacral depression. In addition it arises from the ventral surface of a large superficial aponeu- rosis that attaches along the edges of the synsacral M. LONGUS COLLI DORSALIS THORACICA depression and the spine on the craniolateral tip (LCDT) of the synsacrum, and from an aponeurosis pass-

FIGURE 8a ing craniad from that spine. The muscle is di- rectly adjacent to M. iliocostalis laterally and to This muscle is much reduced in the thorax M. longus colli dorsalis thoracicus medially. Its whereas M. thoracicus ascendens is much en- fibers have two main insertions. The more super- larged. It consists of superficial and deep portions ficial ones attach on the lateral surfaces of a series that are partially separated by aponeuroses of of broad aponeuroses that pass caudoventrally insertion of M. thoracicus ascendens on the spi- from their attachments on the dorsocaudal tips nous processes. Fibers of the superficial portion of the spinous processes of 14 (small), 15, 16, and arise from the dorsal edges of the spinous 17. These aponeuroses separate the superficial processes of the thoracic vertebrae and the first portion of M. longus colli dorsalis thoracica from synsacral vertebra. These aponeuroses become its deep part. The more lateral and deeper fibers successively stronger cranially, and they pass of this muscle insert on the dorsal and ventral craniad almost parallel to the median line. They surfaces of the aponeuroses attaching on the cau- form a series continuous with M. longus colli dal articular processes, which are shared by M. dorsalis, pars caudalis. Insertion of fibers from longus colli dorsalis thoracica. these aponeuroses is on the caudal articular proc- esses of the thoracic vertebrae and on aponeuroses that pass caudally from them. The aponeurosis Muscles of the Trunk and Abdomen of insertion from vertebra 15 is well developed; In Eulampis there are either one or two cervical those from 16 and 17 are very small. As in the ribs (in this discussion we refer to only one side of NUMBER 385 19 the bird). Both are floating ribs, lacking bony M. SCALENUS (S) attachments at their distal ends, and the first, FIGURES 5a, 8a from vertebra 13, is either tiny or absent alto- gether. The second floating rib is much larger. The belly of this muscle arises fleshy from the There are five attached ribs—that is, ribs that transverse process of the penultimate cervical ver- attach on the sternum. The first three are associ- tebra (13) and from the rudimentary floating rib ated with the three free thoracic vertebrae and when it is present on that vertebra. The fibers of the last two with fused vertebrae of the synsa- the stout belly pass caudoventrally and insert crum. Caudal to these ribs are three more that fleshy on the cranial edge of the dorsal two-fifths attach distally on the preceding rib. These are of the floating rib of the last cervical vertebra. the accessory ribs, and they attach further cau- dally on the synsacrum and may be bound to the MM. LEVATORES COST ARUM (L CO) craniolateral edge of the ilium. The dorsal portion FIGURE 8a of each rib is termed the vertebral rib; the ventral portion is the sternal rib. The latter portion is These triangular muscles occupy the dorsal- absent in floating ribs. Uncinate processes attach most portion of the intercostal spaces. The first on vertebral ribs and they are usually associated arises fleshy from the tip of the transverse process only with the attached ribs. of the last cervical vertebra (14). Fibers of the Numbers of thoracic vertebrae, floating ribs, somewhat two-parted belly fan out caudoven- attached ribs, and accessory ribs vary within and trally. The dorsal part inserts fleshy onto the between species. A proper comparison of these lateral and cranial surfaces of the proximal 3mm features and their associated muscles would be a of the first attached vertebral rib. The ventral statistical one, but we have not recorded or ana- part inserts onto the cranial edge of that rib. On lysed quantitative variation of these features in vertebrae 15 and 16 similar bellies arise semiten- this paper. dinously from the tip of the transverse process and from the caudal edge of the corresponding M. OBLIQUUS EXTERNUS ABDOMINUS (O E A) rib. The fibers pass caudoventrally and insert fleshy onto the cranial and lateral surfaces of the FIGURE 8b next caudal vertebral rib and on an aponeurotic sheet connecting successive ribs. The last slip is This is the most superficial muscle of the ab- the smallest and is covered dorsally by a slip of dominal wall. It arises by an aponeurosis from M. iliocostalis and ventrally by the dorsal portion the lateral surfaces of the five attached ribs at the of Mm. intercostales externi. The origin and in- level of their uncinate processes (processus uncin- sertion are similar to the other slips. atus), from the ventral edge of the base of the uncinate processes, and from the lateral surfaces of the accessory ribs. The aponeurosis of origin MM. INTERCOSTALES EXTERNI (I E) from the attached ribs quickly gives rise to fleshy FIGURE 8a,c fasciculi. These fasciculi pass caudoventrally and end on short flat aponeuroses that fuse with the These muscles occupy the spaces between ad- superficial dorsolateral aponeurosis on the surface jacent ribs. They arise fleshy from the caudola- of M. pectoralis adjacent to the rib cage, caudally teral surface of a given rib, beginning with the to the caudolateral angle of the sternal plate floating rib from vertebra 14. The first belly arises (corpus sterni). Caudal to that point the belly fleshy from that entire rib and by an aponeurosis ends on an aponeurosis that meets its counterpart from its tip. The fibers of the belly pass caudov- from the other side at the midline and is closely entrally and insert fleshy on the cranial surface of applied to M. rectus abdominus. the first attached vertebral rib between the ven- 20 SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY tral border of M. levator costarum and the artic- M. COSTOSTERNALIS (CST) ulation with the sternal rib. The next four slips of FIGURE 8c,d this muscle arise fleshy from the entire caudal Pars minor is absent in hummingbirds. surface of the uncinate process and its vertebral PARS MAJOR (CST MA).—This strong, cylin- rib ventrally almost to the articulation with the drical, unipennate muscle lies medial to the ster- sternal ribs. Parallel fibers pass caudoventrally nal ribs. It arises fleshy and by a superficial and insert fleshy on the cranial surface of the medial aponeurosis from the craniolateral process ventral half of the next caudal uncinate process of the sternum (processus craniolateralis). The and the cranial edge of its rib ventrally to the cranialmost fibers from the aponeurosis of origin articulation with the sternal rib. The origins of form a strap-like belly to the first sternal rib near the third, fourth, and fifth bellies of this muscle its articulation with the vertebral rib. Fibers aris- are aponeurotic in the region of the junction of ing more caudally from the aponeurosis form a the uncinate process and the rib. This tends to series of slips to the second, third, and fourth separate the bellies into dorsal and ventral por- sternal ribs. tions. The sixth belly consists of completely sep- arate dorsal and ventral portions. The dorsal M. COSTOSEPTALIS (CSP) portion arises from the last uncinate process and FIGURE 8d inserts by means of an aponeurosis onto the lat- This muscle is represented by a series of muscle eral surface of the first accessory rib at about the slips that arise fleshy from the inner aspect of all level of the uncinate processes. The ventral por- the vertebral attached ribs and the first two ac- tion arises by an aponeurosis and by fleshy fibers cessory ribs. Cranially the first two slips arise very from the caudal surface of the fifth attached rib near the articulation with the sternal ribs. Suc- ventral to its uncinate process. It inserts by a ceeding slips arise progressively further dorsally short aponeurosis on the cranial surface of the along the ribs. The small, strap-like or fan-shaped ventral portion of the first accessory proximal rib. slips pass dorsomedially and coalesce so that there The last bellies consist of fleshy slips between the is a continuous fleshy insertion onto the horizon- ventral ends of the vertebral accessory ribs 1-2 tal septum (septum horizontale). See Baumel et and 2-3. The last belly is minute. al. (1979:225) for a diagrammatic cross-section that shows the relations of this muscle. MM. INTERCOSTALES INTERNI (I I) M. RECTUS ABDOMINUS (R A) FIGURE 8a-d FIGURE 8b These muscles occupy the spaces between suc- This muscle arises by a dense aponeurosis from cessive attached ribs and accessory ribs. They the ventral portion of the distal end of the pubis arise from the caudomedial surface of one rib and and from dense connective tissue between the pass caudally to insert along most of the crani- distal ends of the pubes. Fleshy parallel fibers omedial surface of the next caudal rib. At the pass cranially and slightly laterad to insert on the level of the uncinate process the fibers pass cau- caudal edge of the sternum (margo caudalis) from dodorsally. Dorsal to the uncinate process the a point immediately lateral to the midline lat- belly between the first and second attached ribs erally to the widest point of the sternum. is largely aponeurotic. The short fibers of the belly are restricted to the caudal edge of the M. TRANSVERSUS ABDOMINUS (T AB) muscle. The belly between the second and third ribs dorsal to the uncinate process is more fleshy FIGURE 9b but the cranial edge is partly aponeurotic. The This is the deepest of the abdominal muscles remaining bellies are completely fleshy. and it lies just cranial to the distal end of the NUMBER 385 21 pubis. The muscle arises fleshy from the ventral, lower surface of a superficial aponeurosis that edge of the distal few millimeters of the pubis. covers the cranial part of the belly. The muscle The fibers of the 3 mm long belly pass medially lies just lateral to the midline and is the most parallel to the pubis to end on a midline raphe superficial of the dorsal tail muscles. Separate (linea alba) that extends from the interpubic fasciculi pass caudomedially dorsal to the trans- connective tissue to the caudal end of the ster- verse processes of the caudal vertebrae. They num. insert tendinous on each of the spinous processes In Heliodoxa the belly is relatively wider than of the caudal vertebrae and on the craniomedial in the other species. surface of the pygostyle. The cranial portion of the deeper part of this M. OBLIQUUS INTERNUS ABDOMINUS (O I A) muscle lies deep and lateral to the insertion of the portion described above. It is largely obscured by FIGURE 8b the uropygial gland (glandula uropygialis). This This sheet of muscle arises fleshy from the portion arises fleshy from the bases of the trans- entire length of the pubis as far caudad as the verse processes of the first four caudal vertebrae. lateral border of M. rectus abdominus. Fibers of The fan-shaped belly passes caudolaterally and the belly pass cranioventrally to insert on the inserts by a short tendon onto the calamus of each caudal edge of all but the distal tip of the last of the five rectrices. accessory vertebral rib. M. LATERALIS CAUDAE (LA C)

Muscles of the Tail FIGURE 9a-c

M. BULBI RECTRICIUM (B R) This muscle arises fleshy from the lateralmost portion of the fused transverse processes of the FIGURE 9c-e two caudalmost synsacral vertebrae and the first This muscle arises from a sheet of connective free caudal vertebra, from an aponeurosis that tissue that extends from the distal end of the connects these transverse processes, and from the pygostyle (pygostylus) across the ventral surfaces medial edge of the ilium opposite the laterally of the medial four rectrices. Fleshy fibers pass projecting processus terminalis illi. The nearly craniolaterally to the ventral surfaces of the lat- parallel fibers pass caudally and slightly laterad eral four rectrices and to a connective tissue en- lateral to the uropygial gland to insert fleshy on velope that encloses the bases of those four feath- to the lateral edge of the base of the outermost ers. A distinct lateral slip arises from the dorso- rectrix just cranial to M. pubocaudalis externus. lateral portion of this connective tissue envelope. Its fleshy fibers ensheath the base of the lateral- M. DEPRESSOR CAUDAE (D C) most rectrix and pass distally to attach along the FIGURE 9a,d ventrolateral surface of the base of that feather. This muscle consists of a superficial and a deep M. LEVATOR CAUDAE (LE C) portion. The superficial portion arises fleshy from

FIGURE 9a,b the fused lateral border of the last three transverse processes of the synsacrum and from the ventro- This large muscle arises fleshy from the dorso- lateral surfaces of those transverse processes. In medial surface of the synsacrum beginning at the addition, fibers originate from the ventral surface level of the acetabulum, from the dorsomedial of the lateral two-thirds of the transverse processes portion of the transverse processes of the caudal of all caudal vertebrae. Fibers pass caudomedially vertebrae (vertebrae caudales), and from the and attach on the ventral surface of a strong 22 SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY

superficial aponeurotic sheet that is common to medially and end on a tendinous intersection at the right and left muscles. This sheet forms a sling about the level of the cloaca. Fleshy fibers con- under the body of the pygostyle. Fibers from the tinue dorsally from the intersection to insert on last transverse process attach on the lateral fork an aponeurotic sheet that connects the caudola- of the ventral process of the pygostyle. These teral border of the oval bone to the bases of the fibers blend with those of the deep portion of the lateral four rectrices by distinct fasciculi. In ad- muscle. A flat, oval bone lies imbedded in the dition a strap-like tendon penetrates this aponeu- caudoventrolateral porton of the aponeurotic rotic sheet between the caudalmost two fasciculi sheet. A short, stout tendon joins the caudal end and inserts on the caudolateral edge of the blade of the oval bone with the lateral process of the of the pygostyle (lamina pygostyli) midway be- base of the pygostyle (basis pygostyli). Flat ten- tween the base and the tip. dinous fasciculi pass caudolaterally from the apo- The tendinous intersection mentioned above is neurotic sheet and oval bone to the bases of all continuous with a thin aponeurotic sheet, the but the medial rectrix (see also M. pubocaudalis supracloacal septum (septum supracloacale), that internus). passes across the dorsal surface of the cloaca. The deep portion of this muscle arises from the Caudally this septum is overlain by the cranial ventral surface of the bodies of the caudal verte- portion of M. sphincter cloacae. brae and from the ventral surfaces of the medial third of the transverse processes of caudal verte- M. TRANSVERSUS CLOACAE (T C)

brae 2-5. The medial fibers pass caudally to insert FIGURE 9b,c tendinously onto the ventral processes of the last three caudal vertebrae. Fibers from the transverse This superficial, sheet-like muscle has two parts processes of these vertebrae pass caudomedially that have different origins and insertions but that to insert on the ventrolateral surface of the base are fused in their midportion. The larger, or of the pygostyle and on the ventral process of that ventral, part of this muscle arises by an aponeu- bone deep to the tendon from the oval bone. rosis from the caudalmost portion of the ischium and by fleshy fibers from the dorsal surface of the caudal third of the pubis. Parallel fibers pass M. PUBOCAUDALIS EXTERNUS (P E) caudomedially superficial to M. pubocaudalis ex- FIGURE 9a-c ternus and end on an aponeurosis just cranial to the distal end of the pubis. This aponeurosis This muscle has a fleshy origin from the caudal continues ventral to the cloaca and meets the portion of the ischium and along the caudal aponeurosis from the other side. portion of the pubis almost to its tip. The belly In Eulampis the dorsal belly is a small band of passes caudodorsally superficial to M. pubocau- muscle, 4 mm long and 0.25 mm wide, that arises dalis internus and tapers slightly to a short, flat fleshy from the terminal process of the ilium tendon. The insertion is on the calamus of the (processus terminalis illi) just dorsal to the caudal outermost rectrix immediately caudal to that of margin of the origin of M. iliofibularis. The par- M. lateralis caudae. allel fibers pass caudally superficial to the belly of M. caudofemoralis. The belly ends on a tendon M. PUBOCAUDALIS INTERNUS (P I) that fuses with the dorsal edge of the aponeurosis

FIGURE 9b-d of origin of the ventral part of the muscle. Cau- dally, the aponeurosis of the dorsal portion forms This muscle has a fleshy origin from the caudal a belly that separates from the ventral portion portion of the ischium and from the entire dorsal and passes deep to M. sphincter cloacae, curves surface of the pubis distal to the ischiopubic medially, and inserts on the caudodorsal wall of juncture. The fibers of the belly converge dorso- the cloaca. NUMBER 385 23

The cranial belly is absent in Patagona and is been used for the points of attachment of M. represented only by an aponeurotic band. In extensor metacarpi radialis and M. tensor pro- Heliodoxa the cranial belly is markedly enlarged. patagialis, pars brevis on the humerus. We avoid those terms, and instead refer to the process of M. LEVATOR CLOACAE (L CL) extensor metacarpi radialis and the tubercle of tensor propatagialis, pars brevis because these This muscle is absent in hummingbirds. points are widely separated in the humerus of hummingbirds and because the homology with M. SPHINCTER CLOACAE (S CL) bony projections on the humerus of other birds is

FIGURE 9b uncertain.

This band of muscle completely encircles the M. LATISSIMUS DORSI (L D) cloaca. Cranioventrally, fibers end on a ventral aponeurotic sheet that is continuous with the FIGURES \0a-c, 15a caudal aponeurosis of the main portion of M. This muscle consists of two parts. transversus cloacae. PARS CAUDALIS (L D CA).—This is a slightly fan-shaped muscle that arises by a thin aponeu- Muscles of the Forelimb rosis from the spinous processes and interspinous ligaments of the first three thoracic vertebrae. Muscles of the wing and shoulder of humming- The belly passes laterally superficial to M. rhom- birds have received more attention than those of boideus superficialis, tapers to a narrow tendon, other body regions. Those associated with the and inserts on a crest at the base of the bicipital shoulder were described in abbreviated form for crest just proximal to the origin of the dorsal head the Long-tailed Hermit (Phaethornis superciliosus) of M. humerotriceps. by Fiirbringer (1888), but with six exceptions, PARS CRANIALIS (L D CR).—This is a thin band were not illustrated. An ostensibly complete de- of muscle less than 1 mm wide. It arises by a thin scription of the wing muscles of swifts, with rather aponeurosis from the spinous processes and inter- detailed comparative notes for hummingbirds spinous ligaments of the last cervical and first and other groups, was published by Buri (1900). thoracic vertebrae, passes laterally superficial to This work included three figures that showed pars caudalis, and inserts on the humerus along most of the wing and shoulder muscles of the the dorsomedial margin of M. humerotriceps lat- Rufous Hummingbird (Selasphorus rufus). Cohn eral to the insertion of pars caudalis. (1968) described and discussed only those wing In Calliphlox the origin of pars cranialis is from muscles that she regarded as demonstrating dif- the last cervical vertebra only. Buri (1900) stated ferences in wing action between swifts and hum- that the origin (presumably of pars caudalis) was mingbirds (primarily Patagona gigas), but that from the last cervical and first two thoracic ver- included 35 of the 40 muscles of the wing. George tebrae with "no distinct humeral insertion." and Berger (1966) noted unusual features of cer- tain wing muscles of Eugenes Julgens (based on Berger's dissections) but did not provide full de- M. RHOMBOIDEUS SUPERFICIALIS (R S) scriptions or illustrations. A detailed study of FIGURES 10a, 11, 13 variation of M. tensor propatagialis, pars brevis in hummingbirds and swifts was undertaken by This rhomboid-shaped muscle arises by an Zusi and Bentz (1982), and of the structure of the aponeurosis from the spinous processes and inter- humeroulnar pulley by Bentz and Zusi (1982). spinous ligaments of the last two cervical and the The terms ectepicondylar process, lateral epi- first three thoracic vertebrae. Caudally the origin condyle, and dorsal supracondylar process have is between the aponeurosis of origin of M. latis- 24 SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY simus dorsi, pars caudalis and M. rhomboideus pass craniodorsally deep to the belly of M. scap- profundus. The belly passes craniolaterally to ulohumeralis caudalis and join on a thin apo- insert on the dorsal surface of the cranial half of neurosis that passes between the caudal portion the scapula. of the two heads of M. subscapularis. The inser- Buri stated that the origin in the Trochilidae tion is on the dorsomedial surface of the scapula is from the 13th, 14th, and 15th vertebrae, which just cranial to the midpoint of that bone. are the last two cervical and first thoracic verte- PARS CAUDALIS (S S CA).—This belly is the brae. According to Cohn (1968) the origin is from larger portion of this two part complex. The fan- the last two cervical and first two thoracic verte- shaped belly arises fleshy from the lateral surfaces brae. of the second, third, fourth, and fifth attached ribs. The fibers converge as they proceed dorsally to insert on the ventral and lateral edges of the M. RHOMBOIDEUS PROFUNDUS (R P) caudal portion of the scapula. The caudal fibers FIGURES 8b, 10a, 11 have a fleshy insertion and the cranial fibers insert by a flat tendon. This muscle arises by an aponeurosis from the Cohn (1968:83) stated that the insertion of pars spinous processes and interspinous ligaments of cranialis was "displaced mediad onto the deep the first three thoracic vertebrae deep to the surface of the scapula by the great development caudal portion of M. rhomboideus superficialis. of the external head of M. subscapularis." We The belly passes caudolaterally to insert fleshy found no lateral head to M. subscapularis. onto the dorsomedial surface of the caudal third of the scapula. M. SCAPULOHUMERALIS CRANIALIS (SH CR)

MM. SERRATI FIGURES lOa-c, 13, 15a This small, fan-shaped muscle arises fleshy M. serratus profundus (S P) from the lateral and ventral surfaces of the cranial FIGURES 8a, 10a, 11 2 mm of the scapula just cranial to the belly of M. subscapularis. The belly lies between the ten- This muscle arises fleshy from the lateral por- don of insertion of M. latissimus dorsi, pars cau- tion of the floating rib of vertebra 14 and from dalis and the belly of M. subscapularis. It passes the lateral portion of the first attached rib dorsal between the two heads of M. humerotriceps and to its uncinate process. The parallel-fibered fas- inserts fleshy in a caudal depression at the base of ciculi pass caudally to insert fleshy on the medial the bicipital crest. surface of the distal portion of the scapula just cranial and deep to the cranial half of the inser- M. SCAPULOHUMERALIS CAUDALIS (SH CA) tion of M. rhomboideus profundus. FIGURES 8*, 10a,

M. serratus superficialis (S S) This large unipennate muscle arises fleshy from

FIGURES 8a-c, 10a, 11 the lateral and ventral surfaces of the blade of the scapula (corpus scapulae: facies lateralis). The This muscle consists of two independent bellies. central portion of the belly also arises from the PARS CRANIALIS (S S CR).—This belly origi- medial surface of the scapula ventral to the at- nates by two heads. The cranial head arises fleshy tachment of M. serratus superficialis, pars crani- from the ventral portion of the floating rib of alis. The origin extends from the caudal margin vertebra 14. The caudal head originates by fleshy of the belly of M. scapulohumeralis cranialis cau- fibers from the first attached rib at the level of its dally to a point immediately cranial to the inser- uncinate process. The two parallel-fibered heads tion of M. serratus superficialis, pars caudalis. NUMBER 385 25

The fibers of the belly pass cranioventrally to that inserts on the dorsal head of the bicipital insert on the medial surface of a large, superficial crest of the humerus ventral to the insertions of aponeurosis that ends on a short tendon of inser- Mm. subscapularis and scapulohumeralis cau- tion. The insertion is on the ventral head of the dalis. bicipital crest of the humerus ventral to the inser- tion of M. subcoracoideus. The bicipital crest of M. CORACOBRACHIALIS CRANIALIS (C CR) the humerus in most trochiline hummingbirds is slightly or distinctly notched, resulting in a dorsal FIGURES 10, 12a A 156 acoidal ligament (ligamentum sternocoracoi- This is the largest muscle of the body in all deum longum). These two heads join on a tendon flying birds and it is especially large in humming- 26 SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY birds. It consists of two parts. The large main ment of M. pectoralis. The tendon contains a belly has a fleshy origin from a limited area of sesamoid at a point just after the tendon's emer- the pectoral girdle: from the caudolateral portion gence from the canal. of the sternum lateral to the corporal intermus- We found no sesamoid in Metallura. Develop- cular line (linea intermuscularis [dorsalis]), from ment of the sesamoid in the genera examined the keel of the sternum (carina sterni) ventral to appeared to vary. Cohn (1968) stated that a the carinal intermuscular line (linea intermuscu- sesamoid was present in the "the most advanced" laris [ventralis]), and from the adjacent sterno- genera. coracoclavicular membrane (membrana sterno- Buri (1900) saw the basal two-thirds of the coracoclavicularis). In addition, fibers arise from ventral side of the coracoid as a site of origin. a ventral, superficial aponeurosis that arises from the ventral edge of the keel and from a strong M. STERNOCORACOIDEUS (SC) aponeurosis arising from the corporal intermus- cular line. The fibers of the belly converge onto According to Beddard (1898:85,224) and Cohn a flattened, internal tendon that inserts on the (1968:92) this muscle is absent in hummingbirds. cranial surface of the deltoid crest of the humerus. George and Berger (1966:316) did not find it in Deep and cranial to the main belly is an "an- Eugenes fulgens, and it was absent in Eulampis as terior" component correctly described by Cohn well as all other genera examined. (1968:86). It arises fleshy from the dorsal surface of the cranial 3 mm of the sternal keel, from the M. TENSOR PROPATAGIALIS (T P) caudodorsal surface of the clavicle (clavicula) along most of its length, and from the sternocor- FIGURES 106-*, 126, 14c, 156 acoclavicular membrane. The fibers of the belly This muscle consists of two parts. pass laterally and converge onto a short tendon PARS LONGA (T P L).—This part arises fleshy that fuses with the tendon of insertion of the main from the clavicle just ventral to the head. The belly just prior to that tendon's insertion on the small, parallel-fibered belly ends on a thin tendon deltoid crest of the humerus. The belly of M. (tendo longa) that passes distally in the propata- tensor propatagialis, pars longa, lies superficial to gium. The tendon then fuses with the distal end the cranial portion of this component. of the belly of M. extensor metacarpi radialis and Buri (1900) also stated that the presternal part continues along the tendon of that muscle to of the muscle consisted of a stratum profundum insert on the extensor process of the carpometa- and stratum superficiale. Pars propatagialis lon- carpus (processus extensorius). Dense fascia in gus and brevis are absent in hummingbirds. this area may extend the functional insertion of this muscle onto the proximal portion of the M. SUPRACORACOIDEUS (SUP) alular phalanx (phalanx digiti alulae). As in most FIGURES \Ob,e, 126, 13, 15a birds, pars brevis is much longer than pars longa. PARS BREVIS (T P B).—This part arises by a This bipennate muscle is about half as large as short tendon from the dorsal edge of the head of M. pectoralis. It arises fleshy from the lateral the coracoid immediately dorsal to the origin of surface of the sternum, between the corporal and M. coracobrachialis cranialis. The nearly parallel carinal intermuscular lines, and from the caudo- fibers of the 5 mm long, 2.5 mm wide belly pass ventral portion of the sternocoracoclavicular distally and end on a central aponeurosis that membrane. The fibers converge onto a strong fuses with an internal aponeurosis of M. extensor tendon that passes dorsally through a coracoidal metacarpi radialis. At this point of fusion tendo canal (canalis triosseus) and inserts on the caudal brevis is formed. This tendon of insertion of tensor surface of the deltoid crest opposite the attach- propatagialis, pars brevis exhibits variation NUMBER 385 27 within hummingbirds (Zusi and Bentz, 1982). distally caudal to the tendon of insertion of M. The proximal portion of the tendon passes prox- supracoracoideus and inserts fleshy on the distal imally superficial to the belly of M. extensor end of the deltoid crest of the humerus just dorsal metacarpi radialis and its tendon of origin, and to the insertion of that tendon. inserts on the tubercle of pars brevis (see remarks Neither Buri (1900) nor George and Berger on terminology under "Muscles of the (1966) found this muscle in hummingbirds. Cohn Forelimb"). The distal portion of the tendon (1968) said that it was greatly reduced in both proceeds distally along the dorsal surface of the swifts and hummingbirds. belly of M. extensor metacarpi radialis so that in dorsal view the tendon appears to divide the belly M. DELTOIDEUS MINOR (D MI) of M. extensor metacarpi radialis into cranial and caudal portions. This tendon is bound to the FIGURES 10

humerusjust distal to the midpoint of that bone. large accessory belly from the humerus. The ulnar Distally the belly fans out and ends on an apo- belly of this muscle arises fleshy by two heads neurosis that inserts on the ventral surface of the from the ventral and cranial surfaces of the prox- radius along its distal half. The insertion is just imal end of that bone. These two heads quickly cranial to the insertion of M. pronator profundus. fuse to form a single, spindle-shaped belly that The caudal margin of the belly may be fused a ends on a strong tendon at the distal end of the few millimeters to the accessory belly of M. flexor ulna. The accessory belly of this muscle arises by digitorum profundus. both fleshy and tendinous fibers from the cranio- Buri (1900) reported that there was no special ventral surface of the shaft of the humerus (corpus tubercle of origin. humeri), from the origin of M. pronator superfi- cialis distally along the ventral edge of the hu- M. PRONATOR PROFUNDUS (PR P) merus as far as the midpoint of the humeral origin of ligamentum collaterale ventrale. This FIGURES 14a,6, 156, 166 belly ends on a short, flat tendon that fuses with an aponeurosis of the typical and smaller ulnar The pronator profundus arises by a short ten- belly at about the midpoint of that belly. don from the proximal portion of the epicondylus ventralis of the humerus. The tendon of origin The tendon of insertion passes distally through fans out into a broad aponeurosis that covers the a fibrous loop (1, in Figures I4a,b, \6b) at the end ventral surface of the proximal half of the muscle. of the ulna and proceeds into the manus. It passes The fan-shaped belly inserts fleshy on the ventral deep to a ligament that extends from the distal surface of the distal two-thirds of the radius be- end of the radius to the pisiform process (proces- tween the bellies of M. pronator superficialis and sus pisiformis), passes around that process, and M. extensor longus digiti majoris. extends distally in a groove on the cranial surface of the belly of M. adbuctor digiti majoris. The insertion is on the proximal end of the distal M. FLEXOR DIGITORUM SUPERFICIALIS (F D S) phalanx of the major digit (digitus major). FIGURES 14a,6, 15b Buri (1900) stated that in Metallura there was a sesamoid in the tendon at the metacarpophal- A fleshy belly is absent from this muscle in angeal joint. We did not find it. Eulampis. George and Berger (1966:350) also noted the absence of a belly in Eugenes fulgens, and Buri (1900) and Cohn (1968) reported the muscle M. FLEXOR CARPI ULNARIS (F C U) absent in hummingbirds. The muscle is repre- sented only by a small tendon that arises from FIGURES I4a,b,d, 156, 166 the distal end of the humerus between the tendons of origin of M. pronator profundus and M. flexor This large muscle arises by a well-developed carpi ulnaris. This tendon quickly joins the liga- tendon from the distalmost portion of the epicon- mentum humerocarpale. dylus ventralis of the humerus. The short tendon In Glaucis, Metallura, Heliodoxa, and Thalurania passes under a ligamentous sling (2, in Figure the tendon extends somewhat further distally 14

M. EXTENSOR METACARPI RADIALIS (E M R) three-fourths of the distance down the ulna. At the distal end of the ulna the tendon passes FIGURES 10C, \4a,c,d, \5a,b, \6a,b through a short deep groove under a transverse Buri (1900) stated of this muscle that a division ligament (4, in Figures \4c,d) and continues dis- into two heads was absent. Cohn (1968), however, tally cranial to the origin of M. ulnometacarpalis noted an origin from the ectepicondylar process dorsalis to insert on the processus intermetacar- as well as from the surface of the humerus "distal palis of the carpometacarpus proximal to the and palmar" to that process. We too found that insertion of that muscle. From the proximal end this large bipennate muscle consists of two heads. of the belly a tendinous slip passes caudally. It Caput dorsale arises by a short tendon from a contains a large sesamoid as it passes around the well-developed dorsal process on the shaft of the caudodorsal border of the ulna. On reaching the humerus—the process of E M R (page 23). Caput ventral side of the ulna, it fuses with what remains ventrale arises by both fleshy and tendinous fibers of the humeroulnar pulley and serves as a point from the humeral process and from the shaft of of origin for M. expansor secundariorum (see the humerus distal and ventral to the process of Bentz and Zusi, 1982). E M R. These two heads quickly fuse to form a single belly. The cranialmost fibers of this belly M. EXTENSOR DIGITORUM COMMUNIS (E D C) may arise fleshy from the proximal tendon of M. tensor propatagialis pars brevis. The belly extends FIGURES 10C, 14C, 156, 16a most of the length of the forearm before tapering This hypertrophied muscle has a 2 mm wide to a strong tendon that passes deep to a strong fleshy origin from the craniodorsal surface of the fascial loop (3, in Figure 14f) just before it inserts humerus just distal to the tubercle of tensor pro- on the extensor process of the carpometacarpus. patagialis, pars brevis. A few of the proximal In Glaucis the proximal fibers of the belly of M. fibers of the belly cross the proximal tendon of extensor metacarpi radialis also arise fleshy from M. tensor propatagialis, pars brevis, concealing the dorsal surface of the process of E M R, and the insertion of that tendon. The distalmost fibers the proximal portion of the belly conceals the may arise by a short tendon (or ligament) from proximal portion of the tendon of M. tensor the patella ulnaris. The belly extends most of the propatagialis, pars brevis. In Patagona a fascial length of the forearm and ends on a strong tendon slip arises from the tendon of M. extensor meta- that passes into the manus parallel and cranial to carpi radialis at a point where the tendon of M. a ligamentous ulna-manus band (see under M. tensor propatagialis, pars brevis joins that tendon. extensor longus digiti majoris). The tendon pro- This slip passes caudally superficial to the distal ceeds distally and slightly caudad in a shallow ends of M. extensor digitorum communis and M. groove, often covered with bone, on the cranio- extensor metacarpi ulnaris and fuses with the dorsal surface of the carpometacarpus deep to the fascia surrounding the calami of secondaries 2, 3, tendon of M. extensor longus digiti majoris and and 4, and their coverts. to the ulna-manus band. It then turns caudally through a ligamentous loop (5, in Figure 16a) M. EXTENSOR METACARPI ULNARIS (E M U) that extends from the proximodorsal corner of

FIGURES 14C, \ba,b, 16a the first phalanx to the distal end of the carpo- metacarpus. The tendon then passes cranially This muscle has the most distal origin of all superficial to the loop and encloses a small sesa- muscles arising from the distal end of the lateral moid just before it inserts on a tubercle on the surface of the humerus. The origin is by a tendon cranial surface of the proximal end of the first from the distal end of the epicondylus dorsalis of phalanx of the major digit. the humerus. The belly of the muscle extends Both Buri (1900) and Cohn (1968) noted the distally and gives rise to a strong tendon about presence of the ligamentous loop and the small NUMBER 385 31

sesamoid. They also stated that no branch tendon M. EXTENSOR LONGUS DIGITI MAJORIS (ELD M) is sent to the pollex as it is in most birds. FIGURES I4b,d, \6a,b

M. ULNOMETACARPALIS VENTRALIS (U V) Only pars proximalis is present in humming- birds. This large muscle arises fleshy from most FIGURES \4a,b, \6b of the caudal surface of the radius and tendinous This muscle arises by two equally well-devel- from the caudal edge of the proximal end of the oped heads. The caudal head arises fleshy from radius. The proximal portion of the belly arises most of the caudoventral surface of the shaft of ventral to a flat, transverse, radio-ulnar ligament the ulna. The cranial head arises fleshy from most (ligamentum transversum radio-ulnare). At the of the cranial surface of the ulna and fuses with distal end of the radius the bipennate belly ends the caudal head about one-third the distance on a strong tendon that passes under the inter- along the forearm. The fibers of the unipennate osseal radio-ulnar ligament (ligamentum interos- bellies insert onto a large superficial aponeurosis seum radio-ulnare) and proceeds into the manus that ends on a strong tendon. This tendon passes deep to the ulna-manus band (see below). It then under a fibrous loop (1, in Figures 14a,b, 16b) at passes between the branches of the ulna-manus the distal end of the ulna and passes deep to a band and encloses a sesamoid that is bound to ligament that extends from the radius to the the carpometacarpal-phalangeal joint capsule. pisiform process. The tendon continues cranio- The tendon continues distally and inserts on the dorsally deep to the tendon of M. extensor me- cranial edge of the proximal end of the second tacarpi radialis and inserts on the craniodorsal phalanx of the major digit. Just prior to insertion edge of the proximal end of the carpometacarpus the tendon encloses a second sesamoid that is also just proximal to the extensor process. bound to the joint capsule. Much of the tendon between these two sesamoids is ossified, as noted M. ECTEPICONDYLO-ULNARIS (EC) by Buri (1900) and Cohn (1968). The ulna-manus band is a strong ligament that FIGURES 14rf, \5a,b arises from the dorsal surface of the distal end of This muscle is relatively larger in humming- the ulna and attaches to the bases of the proximal birds than in most other birds. It arises by a wide, four primaries before branching at about the mid- flat tendon from the dorsal aspect of the distal point of the carpometacarpus. One branch passes end of the humerus just proximal to the origin of cranially and inserts on the proximoventral cor- M. extensor metacarpi ulnaris. The fan-shaped ner of the first phalanx of the major digit. The belly passes distally to insert fleshy on the cran- other branch passes caudally, attaches to the iodorsal surface of the middle third of the ulna. bases of primaries five through eight, sends a short tendinous branch distally to the dorsal sur- M. SUPINATOR (SU) face of the first phalanx, and fuses with the ossified portion of the tendon of insertion of M. FIGURES 14rf, \5a,b extensor longus digiti majoris. Although Buri (1900) considered this muscle to In Glaucis the tendon between the sesamoids be weak in hummingbirds, we found it to be was not ossified. relatively well developed, as did George and Ber- ger (1966). It arises by a narrow tendon from the M. EXTENSOR LONGUS ALULAE (E L A) distal end of the humerus just proximal to the FIGURE 14

FIGURE I6a,b M. INTEROSSEUS DORSALIS (I D)

In Eulampis this fan-shaped muscle arises by a FIGURE 16a short, thin tendon from the tuberculum retinaculi on the dorsal surface of the distal end of the ulna. This is a small, bipennate muscle that occupies The insertion is on the caudal surface of the a portion of the intermetacarpal space (spatium carpometacarpus just proximal to the origin of intermetacarpale). It arises fleshy from the facing M. flexor digiti minoris. surfaces of the major and minor metacarpals, George and Berger (1966:371) reported this tapers to a fine tendon, and passes through a muscle absent in Eugenes. Cohn (1968:111) said short bony canal (7, in Figure 16a) at the distal that it was represented by a ligament in most end of the carpometacarpus. The tendon encloses hummingbirds, but that some fleshy fibers were a small sesamoid just before inserting on the present in Patagona. We found it present in all proximodorsal corner of the distal phalanx of the species examined. major digit. The caudal edge of the belly may be fused a few millimeters to the cranial edge of the belly of M. flexor digiti minoris. M. ABDUCTOR ALULAE (AB A)

FIGURES 14a, 16A M. INTEROSSEUS VENTRALIS (I V)

This small muscle arises fleshy from the cau- FIGURE \6a,b doventral surface of the distal end of the tendon of insertion of M. extensor metacarpi radialis. This muscle is slightly larger than M. interos- The spindle-shaped belly tapers to a fine tendon seus dorsalis. It arises fleshy from the caudoven- and inserts on the cranial edge of the alular tral surface of the major metacarpal in the inter- phalanx along most of its length. metacarpal space and in a depression of the cau- doventral surface of the carpometacarpus, proxi- M. ADDUCTOR ALULAE (AD A) mally as far as the pisiform process. The unipen-

FIGURE 16a nate fibers attach along a fine tendon on the caudal edge of the belly. Beyond the belly this This is a very small muscle that has a fleshy tendon passes to the dorsal side of the manus and origin from the cranial surface of the proximal proceeds through the same bony canal (7) as end of the carpometacarpus just distal to the above, caudal to the tendon of insertion of M. extensor process, and inserts fleshy onto the cau- interosseus dorsalis. The tendon continues distally dal surface of the alular phalanx along most of along the caudodorsal border of the proximal its length. phalanx of the major digit. The insertion is on NUMBER 385 33 the caudal surface of the expanded tip of phalanx and fleshy from the cranial margin of the ilium two of the major digit. and the lateral surface of the cranialmost portion of the synsacrum just cranial to the ilium. The M. FLEXOR DIGITI MINORIS (F D M) nearly parallel fibers converge as they approach the knee. The insertion is tendinous on the medial FIGURE I6a,b portion of the patellar crest (crista patellaris). This small muscle arises fleshy from most of the caudal surface of the minor metacarpal (os M. ILIOTIBIALIS LATERALIS (I L) metacarpale minus). The unipennate belly ends FIGURES 17a, 18a on a fine tendon that inserts on the caudal surface of the midpoint of the minor digit (phalanx digiti Only the preacetabular portion of this muscle minoris). is present in Eulampis. This part arises by a broad aponeurosis that extends from the cranial portion of the dorsal iliac crest (crista iliaca dorsalis) Muscles of the Hindlimb caudally along the dorsal margin of the belly on We have found no description of the complete M. iliotrochantericus cranialis as far caudad as hindlimb myology of hummingbirds. Attention the acetabulum. This aponeurosis gives rise to a has previously been focussed on those muscles or nearly parallel-fibered belly at about the level of features that were believed to have systematic the acetabulum. The fibers of the belly pass importance, but full descriptions of even those distally caudal to the belly of M. iliotibialis cran- muscles are lacking. Knowledge of these so-called ialis and may be fused to the belly of M. femo- "formula" muscles, originally discussed by Gar- rotibialis medius for a few millimeters before rod (1873), has been expanded and summarized tapering to a narrow tendon. This tendon passes by George and Berger (1966:233-238). Of ten over the craniolateral margin of the patella and muscles that show interesting patterns of occur- inserts on the lateral portion of the patellar crest rence at the family and subfamily levels, hum- of the tibiotarsus. mingbirds are unique in having only one. These authors list hummingbirds (represented by Eu- MM. ILIOTROCHANTERICI genes) as formula AC (i.e., caudofemoralis and iliotrochantericus medius present), but we found M. iliotrochantericus caudalis (IT CA) iliotrochantericus medius to be absent in the one FIGURE \7a,b phaethornithine genus and six trochiline genera we dissected. Cohn (1968) said it was also absent This bipennate muscle arises fleshy from the in Eugenes and several other genera she dissected. very shallow dorsal iliac fossa (fossa iliacus dor- Different relationships between the tendons of salis). The fibers of the belly converge onto an flexor digitorum longus and flexor hallucis longus internal aponeurosis that ends as a short tendon. in hummingbirds have been described by Gadow The insertion is on the lateral surface of the in Newton (1893-1896), by Lucas (1895), and trochanter of the femur (trochanter femoris). redescribed by Gadow (1895). Our findings agree only with those of Gadow (1895). M. iliotrochantericus cranialis (IT CR)

FIGURES \7a,b, ISb M. ILIOTIBIALIS CRANIALIS (I CR) This small band of parallel fibers arises fleshy FIGURES 17a, 18a from a process on the lateral edge of the preace- This muscle arises by an aponeurosis from the tabular ilium just lateral to the cranial portion of spinous process of the last free thoracic vertebra M. iliotrochantericus caudalis. The dorsal margin 34 SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY of the belly may be fused to the ventral margin M. femorotibialis internus (FT I) of the belly of M. iliotrochantericus caudalis for FIGURE \8a,b a few millimeters. The belly proceeds caudally, This muscle arises fleshy from most of the penetrates the proximal portion of the belly of M. caudomedial surface of the femur beginning at femorotibialis externus, and inserts tendinous on the level of the insertion of M. pubo-ischio-fe- the lateral surface of the femur (os femoris) distal moralis. The unipennate belly widens as it passes to the insertion of M. ischiofemoralis. distally and ends on a tendon that inserts on the medial surface of the cranial cnemial crest (crista M. iliotrochantericus medius (IT M) cnemialis cranialis) of the tibiotarsus. In Metallura and Calliphlox M. pubo-ischio-fe- George and Berger (1966) stated that this mus- moralis inserts well below the proximal end of M. cle was present in Eugenes fulgens. Cohn (1968) femorotibialis internus. reported that it was absent in all the humming- birds she dissected, including Eugenes. We did not M. ILIOFIBULARIS (IF) find it in Eulampis or in the other genera we FIGURE \la-c examined. This triangular muscle arises cranially by an aponeurosis from a point just dorsal to the ace- MM. FEMOROTIBIALES tabulum and by fleshy fibers from the dorsolat- M. femorotibialis externus (FT E) eral iliac crest (crista iliaca dorsolateralis). The belly passes distally, tapers to a strong tendon, FIGURE \la-c and proceeds through the iliofibular loop (ansa M. iliofibularis). The insertion is on a tubercle This muscle arises fleshy from the lateral sur- (tuberculum m. iliofibularis) on the distal end of face of most of the shaft of the femur beginning the fibula. As in most birds, the iliofibular loop just proximal to the insertion of M. iliotrochan- (formerly "biceps loop") is composed of three tericus cranialis. The cranial border of this muscle arms. Two of these arise a short distance apart is fused to the caudal margin of the belly of M. from each other from the lateral surface of the iliotrochantericus medius. The unipennate belly distal end of the femur. The smaller fibular arm ends on an aponeurosis near the distal end of the joins these arms at their distal end. femur. The insertion is on the lateral cnemial crest (crista cnemialis lateralis) and on most of In Metallura, Thalurania, and Calliphlox there are the patellar crest superficial to the insertion of M. two heads of origin. The cranial head arises by femorotibialis medius. an aponeurosis from a small area dorsal to the acetabulum. The caudal head arises by fleshy fibers from the dorsolateral iliac crest. These two M. femorotibialis medius (FT M) heads join about one-fourth the distance down the femur. An artery (arteria ischiadica) and a FIGURES lib, 18a,i nerve (nervus ischiadicus) pass between the two This muscle arises fleshy from the cranial and heads. The main difference between the two- medial surfaces of the femur throughout most of headed condition and that of Eulampis is that, in its length. The proximolateral surface of the mus- the latter, the ischiadic nerve is covered by a thin cle is covered by a superficial aponeurosis. The sheet of muscle fibers. unipennate belly ends on a large tendon that encloses a sesamoid (the os patella) just before it M. FLEXOR CRURIS LATERALIS, PARS PELVICA inserts on the patellar crest of the tibiotarsus deep AND PARS ACCESSORIA and medial to the insertion of M. femorotibialis George and Berger (1966:404) stated that both externus. parts of this muscle were absent in the Apodi- NUMBER 385 35 formes. Neither was present in Eulampis or the lateral tip of an oval bone (see tail musculature) other species studied herein. on the ventral surface of M. depressor caudae. A ligament joins the oval bone to the lateral process M. ISCHIOFEMORALIS (ISF) of the pygostyle.

FIGURE 176 M. PUBO-ISCHIO-FEMORALIS (PIF)

This fan-shaped muscle arises fleshy from the FIGURES \7a,b, 18a,6 lateral surface of the ischium caudal to the iliois- chiatic foramen (foramen ilioischiadicum), and As noted by George and Berger (1966:414), this from a thin membrane overlying the ischiopubic muscle arises as a single muscle mass. There are, fenestra (fenestra ischiopubica). The belly passes however, two separate insertions. The muscle cranially and ends on a stout tendon that inserts arises by fleshy and tendinous fibers from the on the lateral surface of the shaft of the femur ventral and lateral edges of the cranial two-thirds just distal to the tendon of insertion of M. obtur- of the pubis as far caudad as the ischiopubic atorius medialis. juncture. The strap-shaped belly then passes cranioventrally. The cranial fibers insert fleshy onto the caudal surface of the femur from a point M. FLEXOR CRURIS MEDIALIS (F CR M) just distal to the origin of M. caudofemoralis

FIGURES 17a, I8a,b distally to the medial condyle (condylus medialis) of the femur. The caudal fibers insert fleshy on This muscle arises fleshy from the lateral edge the belly and tendon of origin of M. gastrocne- of most of the ischium and lies caudal to the belly mius pars intermedia. of M. iliofibularis. The parallel fibers pass distally In Metallura and Calliphlox the proximal fibers obscuring most of M. pubo-ischio-femoralis and of insertion begin well distal to the proximal limit end on a flat tendon. This tendon passes between of origin of M. femorotibialis internus. the widely separated pars medialis and pars in- termedia of M. gastrocnemius. The tendon di- M. OBTURATORIUS LATERALIS (O L) vides and sends a ventromedial branch to its insertion on the caudal edge of the belly of M. FIGURE Mb gastrocnemius, pars medialis. The proximolateral This muscle consists of two parts in many birds. portion of the tendon inserts on the proximome- Pars dorsalis is not found in Eulampis jugularis. dial surface of the tibiotarsus and on the distal PARS VENTRALIS (O L V).—This part arises by end of the medial collateral ligament (ligamen- fleshy parallel fibers from the proximal end of the tum collaterale mediale). pubis ventral to the obturator foramen (foramen obturatum). The small, 1 mm-long belly passes M. CAUDOFEMORALIS (CF) craniolaterally to insert on the femur distal to the insertion of M. obturatorius medialis. A few fibers FIGURES 9a-d, I7a,b, 186 of the dorsal margin of the belly may be fused to This muscle arises by a thin tendon from the the tendon of M. obturatorius medialis. George caudal surface of the femur about 3 mm from the and Berger (1966:415) apparently also found only proximal end of the bone. The nearly parallel- pars ventralis in Eugenes. fibered belly passes caudodorsally cranial to the belly of M. flexor cruris medialis and then passes M. OBTURATORIUS MEDIALIS (O M)

between the cranial and caudal portions of M. FIGURES 96, 176, 18a transversus cloacae. Ventrolateral to M. depressor caudae, about half way along that muscle, the This bipennate muscle arises fleshy from the belly tapers to a thin tendon that inserts on the dorsomedial surface of the pubis and the ventro- 36 SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY medial edge of the ischium and covers the medial deep to the distal portion of the belly of M. surface of the membrane that closes the ischio- femorotibialis internus. The belly extends about pubic fenestra. The fibers converge onto an inter- one-third the distance down the crus and ends on nal aponeurosis that becomes a stout tendon. The a tendon that forms the central portion of the tendon and fleshy fibers ventral to the tendon common tendon. Much of the surface of the pass laterally through the obturator foramen. The unipennate bellies of pars lateralis and pars me- insertion is on the caudolateral surface of the dialis is covered by superficial aponeuroses. In femur just proximal to the tendon of M. ischio- pars intermedia the aponeurosis covers the deep femoralis. or cranial surface of the belly. These aponeuroses converge to form the tendo m. gastrocnemius that M. ILIOFEMORALIS INTERNUS (IF I) passes distally over the tibial cartilage (cartilago tibialis) to which it is loosely attached. The inser- This muscle is absent in all species studied tion is on the caudal surface of the hypotarsus. herein. George and Berger (1966:418) did not In some specimens of Glaucis, pars medialis find it in Eugenes, and Cohn (1968:122) stated exhibits a poorly defined patellar band. The pa- that it was absent in hummingbirds. tellar band (Raikow, 1976:784) is a band of mus- cle that arises from the patellar ligament (Hga- M. ILIOFEMORALIS EXTERNUS (IF E) mentum patellae) and proceeds around the cra- nial surface of the knee. In Glaucis a few fibers This muscle also is absent in the species studied may arise from the patellar ligament and pass herein. George and Berger (1966:393) reported it over the cranial cnemial crest onto the main belly absent in Eugenes. of pars medialis.

M. GASTROCNEMIUS (G) M. FIBULARIS LONGUS (F L)

FIGURES \7a,c, 18a, 196, 20a This muscle is absent in the species studied herein. George and Berger (1966:429) stated that This muscle consists of three parts. it was absent in the Apodiformes. PARS LATERALIS (G L).—This part has its origin by a short tendon from the lateral surface of the distal end of the femur just proximal to the M. TIBIALIS CRANIALIS (T GR) trochlea fibularis. The tendon is fused to the FIGURES llb,c, I8a,b, 20a,c lateral femoral arm of the iliofibular loop. The belly extends about half the distance down the This muscle lies along the cranial and craniola- crus and ends on a tendon that forms the lateral teral margin of the crus and consists of two heads. portion of the common tendon of this muscle. Caput tibiale arises fleshy from the patellar crest PARS MEDIALIS (G M).—This past arises fleshy of the tibiotarsus and tendinous from the cranial from the cranial cnemial crest of the tibiotarsus, cnemial crest. Fibers of the proximomedial edge from the medial surface of the proximal one-half of the belly arise from the surface of M. extensor of the tibiotarsus and from the medial surface of digitorum longus. The smaller, caudolateral the investing aponeurosis of M. tibialis cranialis. head, caput femorale, arises by a short tendon The belly extends most of the distance down the from the distal end of the lateral femoral condyle crus before tapering to an aponeurosis that forms (condylus lateralis). These heads pass distally in the medial portion of the common tendon. close apposition and fuse to form a common PARS INTERMEDIA (G I).—This part arises by tendon near the distal end of the tibiotarsus, both fleshy and tendinous fibers from an areajust where the tendon passes through a transverse proximal to the internal femoral condyle and ligamentous loop (retinaculum extensorium tibi- NUMBER 385 37 otarsi: 8, in Figures I7b,c, 18b). The insertion is bifurcate and sends a small branch to insert on on a tubercle (tuberositas m. tibialis cranialis) on the proximal end of the third phalanx. The main the cranial surface of the tarsometatarsus about insertion is the same. one-third the distance down that bone. M. FLEXOR PERFORANS ET PERFORATUS DIGITI M. FIBULARIS BREVIS (F B) III (F P P D 3)

FIGURES \7b,c, 20c FIGURES I7b,c, I9a,b, 20d This muscle has a fleshy and tendinous origin This muscle arises by a short tendon from the from the distal tip of the fibula. It also arises by lateral surface of the lateral femoral condyle, by fleshy fibers from the lateral and craniolateral fleshy fibers from the lateral surface of the head surfaces of the tibiotarsus distal to the fibula. The of the fibula, and from the lateral surface of the unipennate belly extends to the distal end of the distal end of that bone. The muscle also arises tibiotarsus where a short tendon is formed. The from an aponeurosis between the bellies of M. tendon crosses the intertarsal joint and inserts on fibularis brevis and M. flexor digitorum longus. a prominent lateral tubercle (tuberositas M. fi- The slender, unipennate belly ends on a tendon bularis longus) on the proximal end of the tarso- that passes through a large, caudolateral canal of metatarsus. the tibial cartilage in company with M. flexor In Metallura the tendon of insertion is longer, perforans et perforatus digiti 3 and M. flexor forming about two-thirds the distance down the perforatus digiti IV, and proceeds distally lateral crus. to the hypotarsus. The tendon continues distally along the tarsometatarsus, becomes thickened at M. EXTENSOR DIGITORUM LONGUS (E D L) the distal end of that bone and then perforates the tendon of M. flexor perforatus digiti HI. The FIGURES 17C, 18£, 19a, 20a,d,e tendon then bifurcates to allow for the passage of This bipennate muscle arises fleshy from the the branch tendon of M. flexor digitorum longus. patellar crest, tendinous from the cranial cnemial The two flat branches thus formed insert on the crest, from the proximal half of the craniolateral lateral and medial corners of the proximal end of and craniomedial surfaces of the tibiotarsus, and the third phalanx of digit III. from the cranial surface of the shaft of the fibula. The belly extends three-fourths the distance down M. FLEXOR PERFORANS ET PERFORATUS DIGITI the crus and ends on a strong tendon that passes II (F P P D 2) under the retinaculum extensorium tibiotarsi. It FIGURES 17b,c, \9a,b, 20d then proceeds through a bony canal (pons supra- tendineus) at the distal end of the tibiotarsus, This small, spindle-shaped muscle lies just cau- crosses the intertarsal joint, and proceeds through dal to M. flexor perforans et perforatus digit III a second bony canal at the proximal end of the and arises by a short tendon from the proximal tarsometatarsus, medial to the tendon of M. ti- portion of the lateral femoral condyle. Three bialis cranialis. The tendon trifurcates about two- other muscles share this origin: M. flexor perfor- thirds the distance down that bone, sending atus digiti II, M. flexor perforatus digiti HI, and branches to all of the foretoes. With the exception M. flexor perforatus digiti IV. The belly extends of the branch to digit III none of these branches one-third the length of the crus and ends on a divides any further. Each passes along the dorsal wide, flat tendon that becomes thread-like. It surface of the phalanges and inserts on the prox- passes through a separate canal of the tibial imal end of the ungual phalanx (phalanx distalis) cartilage and then through a lateral groove or of its respective digit. The branch to digit III does canal of the hypotarsus caudal to the canal of M. 38 SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY flexor digitorum longus. The tendon continues tends distally and ends on a tendon that passes distally along the caudal surface of the tarsome- through a large caudolateral canal of the tibial tatarsus and passes deep to the metatarsus hal- cartilage, lateral to the hypotarsus, and along the lucis (os metatarsale 1). Just distal to that bone caudal surface of the tarsometatarsus. The flat- the tendon perforates the tendon of M. flexor tened tendon divides at the distal end of the perforatus digiti II and then becomes thickened thickened portion of M. flexor perforans et per- at the base of the tarsometatarsus. It then splits foratus digiti III and is perforated by the tendons to allow for the passage of the branch tendon of of the muscle and of M. flexor digitorum longus. M. flexor digitorum longus. The two resulting The insertion is on the medial and lateral surfaces flattened branches insert on the lateral and me- of the proximal end of the second phalanx of digit dial surfaces of the proximal end of the second III. phalanx of digit II. M. PLANTARIS (PL) M. FLEXOR PERFORATUS DIGITI IV (F P D 4) George and Berger (1966:442) reported this FIGURES 17b,c, \9a,b,20c-e muscle absent in Eugenes. It is also absent in all species examined in this study. This muscle has a common tendinous origin with M. flexor perforatus digiti III from the lat- M. FLEXOR PERFORATUS DIGITI II (F P D 2) eral femoral condyle. The spindle-shaped belly passes distally cranial to M. flexor perforatus digit FIGURES Me, \9a,b, 20d III and ends on a thin tendon that passes through This muscle arises by a long, thread-like tendon a large caudolateral canal of the tibial cartilage from the cranial edge of the common tendon of in company with M. flexor perforatus digiti III origin of M. flexor perforatus digiti III, M. flexor and M. flexor perforans et perforatus digiti III. perforans et perforatus digiti II, and M. flexor The tendon passes along the caudolateral surface perforatus digiti IV. This tendon gives rise to a of the tarsometatarsus, becomes thickened, and tiny, spindle-shaped belly that is bounded by the bifurcates at about the midpoint of phalanx one. distal portions of the bellies of M. flexor hallucis The branch tendon of M. flexor digitorum longus longus, M. flexor perforatus digiti IV, and M. passes between the two resulting branches that flexor digitorum longus. The belly ends on a insert on the lateral and medial corners of the slender tendon that passes through a separate proximal end of the third phalanx of digit IV. canal in the tibial cartilage, continues lateral to In Thalurania the belly is very slender and the hypotarsus in a groove or canal, and passes needle-like. down the tarsometatarsus deep to the metatarsus hallucis. The tendon bifurcates and is perforated M. FLEXOR PERFORATUS DIGITI III (F P D 3) by the proximal end of the thickened portion of M. flexor perforans et perforatus digiti II. The FIGURES 17*,

the femur and medial to the iliofibular loop, and digit. The branch to digit III perforates the ten- by a tendon from the medial border of that dons of M. flexor perforatus digiti III and M. depression. The tendon of origin continues dis- flexor perforans et perforatus digiti HI, and con- tally as a broad aponeurosis on the cranial surface tinues distally along the ventral surface of digit of the belly. Most of the caudal surface of the III to insert on the proximal end of the ungual belly is covered by an aponeurosis that extends phalanx of that digit. The branch to digit IV distally to become the tendon of insertion. The perforates the tendon of M. flexor perforatus large fusiform belly extends most of the length of digiti IV at the proximal end of the first phalanx. the crus and ends on a tendon that passes cranial It continues distally to insert on the proximal end to the tibial cartilage and lateral to the base of of the ungual phalanx of digit IV. A single vin- the hypotarsus. As it continues distally it sends a culum arises from the deep surface of each branch strong, tendinous connection to the branch ten- tendon. In each case the vinculum inserts on the don of M. flexor digitorum longus to digit II, just distal end of the penultimate phalanx of the digit. distal to the point of trifurcation. A series of In Heliodoxa the belly extends the entire length thinner tendinous connections is sent to the of the crus. branch tendons of digits III and IV across the point of their bifurcation. The main tendon con- M. FLEXOR HALLUCIS BREVIS (F H B) tinues caudally on to the ventral surface of the FIGURE 20a-c,e hallux. The insertion is on the proximal end of the ungual phalanx of the hallux. This small muscle arises fleshy from the entire medial surface of the hypotarsus, from the distal portion of the lateral surface of the hypotarsus, M. FLEXOR DIGITORUM LONGUS (F D L) and from the caudomedial surface of the proximal FIGURES 17C, 18*, I9a-c, 20c-e 1 mm of the 5 mm long tarsometatarsus. The muscle also arises from the distal end of the The lateral head of this muscle arises fleshy tendon of insertion of M. gastrocnemius. The from the entire caudal surface of the head (caput belly overlaps onto the lateral surface of the fibulae) and shaft (corpus fibulae) of the fibula. tarsometatarsus without arising from it. The bi- The larger medial head arises fleshy from a crest pennate belly tapers to a strong tendon that on the proximocaudal border of the tibiotarsus passes between the metatarsus hallucis and the and from the caudal surface of the proximal half tarsometatarsus and inserts on the proximal end of that bone. These heads fuse after independent of the hallux lateral to the tendon of insertion of courses of a few millimeters. The large, bipennate M. flexor hallucis longus. belly extends three-fourths of the distance down the crus and ends on a strong tendon that passes M. EXTENSOR HALLUCIS LONGUS (E H L) cranial to the tibial cartilage. The tendon contin- FIGURE 20a,b,e ues through a bony canal in the base of the hypotarsus and as it proceeds distally, trifurcates This small muscle arises from a tubercle on the and receives the short tendinous connections from proximal end of the medial surface of the tarso- the tendon of M. flexor hallucis longus described metatarsus cranial to the belly of M. flexor hal- above. lucis brevis. The branch to digit II perforates the tendon of PARS PROXIMALIS (E H L P).—This 4 mm belly M. flexor perforatus digiti II, passes deep to the passes distally and ends on a strong tendon that thickened portion of the tendon of M. flexor proceeds under a fibrous loop (9, in Figure 20b), perforans et perforatus digiti II, and then perfo- and continues distad along the dorsal surface of rates that tendon. The tendon continues distally the hallux. The insertion is on the dorsal surface along the ventral surface of digit II and inserts on of the proximal end of the ungual phalanx of the the proximal end of the ungual phalanx of that hallux. 40 SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY

PARS DISTALIS (E H L D).—This tiny distal interorbital region and extends caudolaterally belly is also present. It arises fleshy from the along the rim of the orbit. The slender, parallel- caudomedial surface of the tarsometatarsus be- fibered belly arises fleshy from the rostral end of tween the metatarsus hallucis and the belly of M. this depression, passes caudally superficial to M. flexor hallucis brevis. The belly passes distally adductor mandibulae externus temporalis, and along the dorsal surface of the metatarsus hallu- bifurcates. cis, passes through the fibrous loop, and ends on PARS INTERSCAPULARIS (C C I).—This dorsal a thin tendon. The insertion is on the dorsal part passes caudally on the skin of the neck and surface of the proximal end of the hallux. inserts on the interscapular feather tract (pteryla In both Metallura and Thalurania the distal belly interscapularis). is unusually large for the size of the bird and in PARS PROPATAGIALIS (G C PR).—The fibers of the former the origin has expanded proximally this part pass caudally in the ventral skin of the along the tarsometatarsus. The distal belly is neck. Just cranial to the belly of M. tensor pro- barely discernible in Glaucis. patagialis, pars longa, the belly ends and a weak tendon is formed. This tendon passes caudally M. ADDUCTOR DIGITI II (AD D 2) superficial to the belly of that muscle and inserts

FIGURE 20C/ on the lateral side of the anterior component of M. pectoralis. This bipennate muscle arises fleshy from most In some forms, e.g., Thalurania, this tendon of the caudolateral surface of the tarsometatarsus continues caudally across the anterior component beginning just distal to the insertion of M. fibu- and inserts on the craniolateralmost corner of the laris brevis. The small belly extends the entire main portion of M. pectoralis. Fiirbringer (1888) length of the tarsometatarsus and ends on a well- did not mention the tendon of this muscle, and developed tendon that passes medially deep to he stated that the insertion was on the clavicle the metatarsus hallucis and the flexor tendons, and the shoulder fascia. and inserts on the proximolateral corner of the first phalanx of digit II. In Heliodoxa the belly is shorter, extending only M. PECTORALIS SUBCUTANEA (P S) half the length of the tarsometatarsus. FIGURES 9b, 12a

Subcutaneous Muscles This muscle has two parts. PARS ABDOMINALIS (P S A).—This part consists Four of the five muscles described below have of a 2 mm wide belly that arises by a thin, broad skeletal attachments on the cranium, clavicle, or tendon from the distal end of the pubis just lateral pubis. The other attaches on the tendon of inser- to the midline. The belly passes cranially and tion of M. pectoralis and thus has an indirect inserts on the skin near the caudal end of the attachment on the humerus. Our findings are in lateral thoracic feather tract. essential agreement with the descriptions of these PARS THORACICA (P S T).—This part arises by muscles for Phaethornis superciliosus by Fiirbringer a tough aponeurosis from the medial surface of (1888). Differences are noted below. the tendon of insertion of M. pectoralis. The aponeurosis passes caudolaterally onto the fleshy M. CUCULLARIS CAPITIS (C C) surface of M. pectoralis where it gives rise to a narrow belly. The belly passes ventrolaterally and FIGURES 2a, 4c fans out to a width of 10 mm as it inserts on the This muscle lies in a depression in the dorso- skin near the middle three-fifths of the lateral lateral surface of the cranium that begins in the thoracic feather tract (pteryla pectoralis). NUMBER 385 41

M. CUCULLARIS CERVICIS, PARS CLAVICULARIS trachea, vertebral column, trunk, abdomen, tail, (C CE C) appendages, and integument. In hummingbirds these muscles number 132, using the terminology FIGURE Wd of Baumel et al. (1979). Here we will isolate some This small muscle arises fleshy from the head of the features that are likely to play an important of the clavicle. It passes dorsally medial to the role in future research. head of the coracoid and then caudally, superfi- SYSTEMATIC STUDIES WITHIN THE TROCHILI- cial to M. rhomboideus superficial is. The inser- DAE.—The following features may prove partic- tion is on the skin of the interscapular feather ularly useful in defining subgroups within hum- tract just lateral to the midline. It does not meet mingbirds. When referring to relative differences its counterpart from the other side at the midline. in size we list only major differences. Fiirbringer (1888) described the muscle as at- Hyoid: The insertion of M. serpihyoideus as a taching on the skin of the proximal two-thirds of single layer, or as two partially overlapping layers. the neck. Jaws: The relative size and internal structure of M. adductor mandibulae externus rostralis M. SERRATUS SUPERFICIALIS, PARS METAPATAGIALIS temporalis; relative development of the belly and (SSM) the extent of insertion of pars ventralis of the same muscle; the relative size and extent of inser- This muscle is absent in the species studied tion of M. pterygoideus dorsalis medialis. herein. According to Cohn (1968) it is absent in Neck: The pattern of vertebral origins of M. all hummingbirds. longus colli dorsalis cranialis, M. rectus capitis lateralis, and M. complexus. M. CONSTRICTOR COLLI, PARS INTERMANDIBULARIS Tail: Relative development of the belly of the (CO C I) dorsal portion of M. transversus cloacae. Wing: Patterns of variation in the proximal FIGURE 4a and distal tendons of M. tensor propatagialis, This is the rostralmost portion of M. constrictor pars brevis (Zusi and Bentz, 1982); the extent of colli. It arises from the transverse nuchal crest the fleshy belly of M. extensor metacarpi radialis immediately rostral to the dorsal portion of M. at its origin; presence or absence of a sesamoid in serpihyoideus, and dorsomedially on the crest to the tendon of M. supracoracoideus; configuration its intersection with M. stylohyoideus. The thin, of insertions of M. subscapularis, M. subcoracoi- strap-like muscle passes ventrally and then me- deus, M. coracobrachialis caudalis, M. scapulo- dially as it becomes bound to the skin of the humeralis caudalis, and M. humerotriceps in re- throat and meets its opposite member on a me- lation to a notched versus an unnotched bicipital dian raphe just caudal to M. serpihyoideus. This crest (Cohn, 1968). is probably M. cucullaris caput portion of Bock Leg: Extent of insertion of M. pubo-ischio- et al. (1973). femoralis; one versus two heads of origin of M. iliofibularis; presence or absence of the patellar band of M. gastrocnemius; relative length of the Discussion tendon of M. fibularis brevis; relative develop- The main purpose of this paper is to provide ment of the distal belly of extensor hallucis lon- background data for future studies of phylogeny gus; extent of origin of M. adductor digiti II. and adaptation of hummingbirds. Toward that PHYLOGENETIC RELATIONSHIPS OF THE TROCHIL- end we have described all muscles attaching on IDAE.—The search for features that are unique to the axial, appendicular, and hyoid skeletons that hummingbirds or to hummingbirds and only one are associated with the eye, jaws, tongue, hyoid, or a few other groups must involve broad com- 42 SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY parisons, many of which cannot be made at this well developed, occupying the entire ventrolateral time for lack of published information. Instead, surface of the centrum that is occupied by a slip we shall focus on some peculiarities of humming- of M. longus colli ventralis in some oscines and birds that are brought to light by comparison other birds. The caudal portion of M. rectus with oscine Passeriformes, for which information capitis lateralis in hummingbirds, but not in os- on all muscles from at least a few species is cines or in other orders studied to date, takes its available (Shufeldt, 1890; Beecher, 1953; Fiedler, origin from the tendon of M. longus colli ventralis 1951; Bock, 1972; Bock and Morioka, 1971; Bock rather than from a vertebral ventral process. In et al., 1973; Richards and Bock, 1973; Engels, hummingbirds the slips of M. longus colli ven- 1938; Palmgren, 1949; Hudson, 1937; Hudson tralis lack a fasciculus from the centrum of the and Lanzillotti, 1955; Raikow, 1976, 1977, 1978; vertebra caudal to that of insertion, such as that Berger, 1956, 1957). We also comment on the found in some oscines and in other orders; in Apodidae insofar as such information is available addition, hummingbirds differ from oscines in from Buri (1900), Hudson (1937), George and having the first section of the neck served by long Berger (1966), Cohn (1968), Morioka (1974), and slips from the third section or the thorax, as Burton (1971), and on birds in general from opposed to only short slips from the second sec- George and Berger (1966) and Hofer (1950). tion. An unusual feature of hummingbirds is the Hyoid: Origin of M. serpihyoideus from the predominance of muscle fibers inserting on the exoccipital region of the skull in hummingbirds full extent of the first long tendon of M. longus differs from that of most oscines, in which the colli ventralis and the virtual absence of fibers to muscle attaches on the base of the cranium or all but the cranial and caudal ends of the next lower jaw. Hummingbirds also differ from oscines four long tendons. in having the interceratobranchialis insert on the Tail: Hummingbirds have a pair of flat, oval basibranchiale caudale whereas in oscines the bones (noted by Cohn, 1968) lying ventrolateral muscle forms a sling without bony attachment. to the caudal vertebrae on the surface of M. M. hypoglossus obliquus originates from the bas- depressor caudae. Analogous bones occur also in ibranchiale rostrale in hummingbirds; in oscines the Falconidae (Richardson, 1972). Insertion of it may originate from that bone or from an M. caudofemoralis on these bones is apparently unattached sling. Unlike the oscines, tracheal and confined to hummingbirds and falconids. laryngeal muscles of hummingbirds have no at- Abdomen: M. transversus abdominus is ex- tachment on the hyoid apparatus. tremely reduced in hummingbirds, perhaps in Jaws: In hummingbirds the absence of M. relation to their expanded sternum. A feature of adductor mandibulae externus caudalis and the some interest is the craniodorsal portion of M. unusual development of M. adductor mandibu- transversus cloacae and its fleshy belly within and lae caudalis agrees with swifts, but not with os- among families (Zusi, unpublished data). Hum- cines and many other birds. In both swifts and mingbirds more closely resemble swifts than os- hummingbirds the structure of the pterygoideus cines in this feature. complex is relatively simple, but the two groups Wing: In most birds M. biceps brachii origi- differ in the form of M. pterygoideus ventralis nates from the humerus and from the coracoid, lateralis and M. pterygoideus dorsalis medialis and inserts on both the radius and ulna. In (see Morioka, 1974). hummingbirds it also has a double origin, con- Neck: The structure of M. splenius capitis in trary to published statements, and it inserts only swifts, crested-swifts (Hemiprocnidae), humming- on the ulna. Cohn (1968) reported that in swifts birds, owlet-frogmouths (Aegothelidae), and it inserts on the radius and ulna, or only on the hemipode-quails (Turnicidae) differs from other radius. M. flexor digitorum superficialis is repre- birds in being cruciform at its origin (Burton, sented in hummingbirds only by a tendon that 1971). In hummingbirds the inclusi are especially connects the humerus and the ligamentum hu- NUMBER 385 43 merocarpale whereas swifts and most other birds that it is no wonder that previous workers over- have a fleshy belly that arises from the humerus looked it. Its needle-like belly arises from the ulna. and inserts by a tendon on the proximal phalanx In many non-passerine birds the muscle is pro- of the major digit. Some forelimb muscles are portionately larger and has two heads of origin, greatly enlarged in hummingbirds. In relation to one from the ulna and another from the radius. M. pectoralis, M. supracoracoideus is larger in In most birds M. expansor secundariorum hummingbirds than in any other bird. It is also arises from the distal end of the humerus, the enlarged in swifts in relation to the powered humeroulnar pulley, or both, and in some it upstroke of their wings (Cohn, 1968). M. coraco- receives a tendon from the axilla. In humming- brachialis cranialis is absent in many passerines birds the muscle arises from what remains of the but well developed in hummingbirds. Apparently pulley, and it lacks the axillary tendon (Bentz it is also large in swifts and caprimulgids. Another and Zusi, 1982). In most birds a short, tendinous hypertrophied muscle in hummingbirds and slip, the ulnar anchor, is present on M. extensor swifts is M. tensor propatagialis pars brevis. In metacarpi ulnaris, but in hummingbirds this an- the former, and in some swifts, it makes a broad, chor is absent. In passerines and most other birds fleshy contact with the belly of M. extensor me- the tendon of insertion of M. extensor digitorum tacarpi radialis. The relationship of these two communis sends a branch to the pollex. In hum- muscles in swifts and hummingbirds has been mingbirds there is no branch to the pollex and described previously (Zusi and Bentz, 1982). M. the muscle is hypertrophied. flexor digitorum profundus is comprised of not Hindlimb: Hummingbirds are noted for the only a typical belly that arises by two heads from lack of numerous leg muscles found in other birds the ulna, but also an accessory belly. This acces- (see list below). A muscle that is absent in oscines sory belly appears to be unique to hummingbirds but present in hummingbirds is M. adductor and swifts (Cohn, 1968:102) although the muscle digiti II. The muscle is also absent in Chaetura is not identical in the two families. (swift) and Chordeiles (nighthawk). M. femoroti- At least three muscles of the forearm are mark- bialis internus has two heads of origin in some edly reduced in size. These are M. deltoideus oscines, but only a single head in hummingbirds. major, M. deltoideus minor, and M. extensor Similarly, in the former M. pubo-ischio-femoralis longus allulae. In the first two muscles the reduc- typically has two bellies whereas in the latter the tion is dramatic in both hummingbirds and muscle is divided only at its insertion. A partial swifts. In most birds, including oscines, M. del- origin of M. extensor digitorum longus from the toideus major consists of two heads, one arising fibula as seen in hummingbirds is absent in swifts, from the clavicle and the other from os humeros- passerines, and most other birds (Hudson, 1937). capulare (fibrocartilago humerocapsularis). In oscines, the tendon of this muscle branches Hummingbirds have only the scapular head. In extensively and sends various tendinous slips to passerines the bellies extend most of the length of the interphalangeal joint capsules, but in Chaetura the humerus and insert along the shaft. However, and hummingbirds the tendons attach mainly on in hummingbirds and swifts the shaft of the the ungual phalanges. humerus has been extremely shortened and mus- Striking variation also occurs in M. flexor hal- cles that are confined to the distal end of the lucis longus and its relations with M. flexor digi- humerus in other birds have migrated proximally torum longus. According to George and Berger in hummingbirds and swifts, obliterating the (1966:444) M. flexor hallucis longus arises by a usual area of attachment of the deltoids. In hum- single head from the intercondyloid region of the mingbirds the two small muscles lie on either side femur in most non-passerines. In Chordeiles and of the tendon of M. supracoracoideus and insert Chaetura the entire tendon fuses with that of M. near its attachment. The third muscle, M. exten- flexor digitorum longus, and the common tendon sor longus allulae, is so small in hummingbirds then splits into four branches to supply all of the 44 SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY toes. In many oscines there are three heads of cies); pterygoideus, pars dorsalis lateralis; ptery- origin: from the intercondyloid region, from the goideus, pars retractor; longus colli dorsalis pro- external femoral condyle, and from the distal end fundus; levator cloacae; serratus superficialis, of the femur. Also, in passerines (except Eury- pars costohumeralis; pectoralis, pars propatagialis laimidae) there is no connection between the longus and brevis; sternocoracoideus, iliotibialis tendons of M. flexor hallucis longus and M. flexor lateralis (acetabular and postacetabular parts); digitorum longus. In hummingbirds there are two iliotrochantericus medius; flexor cruris lateralis, heads of origin of M. flexor hallucis longus: one pars pelvica; flexor cruris lateralis, pars accesso- fleshy from the femur proximal to the external ria; iliofemoralis internus; fibularis longus; plan- condyle, and a second medial to the first head. taris; and lumbricalis. The tendons of the two muscles have tendinous ADAPTATIONS.—In this study we have excluded connections at the point of trifurcation of M. species that show bizarre modifications of the bill, flexor digitorum longus, and M. flexor hallucis wings, or tail in order to avoid describing features longus continues distally to insert on the hallux. that relate to special adaptations. Such features Our description of the relations of these two should be studied separately and in depth. Nev- tendons in hummingbirds agrees with that of ertheless, we suggest that most or all of the differ- Gadow (1895). Hummingbirds most closely re- ences among the Trochilidae, listed above, will semble the Type 1 tendon arrangement of Gadow prove to have an adaptive explanation, as will (Newton, 1893-1896), but they are not identical some of the differences between hummingbirds to that type. and other families. Cohn (1964) has discussed the M. flexor perforatus digiti II is extremely small functional significance of various modifications of in hummingbirds and it is lacking in Chaetura. the wing in swifts and hummingbirds, and The tendon of this muscle is perforated by the Scharnke (1931) and others have dealt with the tendons of M. flexor perforans et perforatus digiti tongue and hyoid apparatus. Yet, both of these II and M. flexor digitorum longus in humming- adaptive complexes need further study. We have birds and in some, but not all, passerines. shown that the Trochilidae represent a rich source MUSCLES ABSENT IN HUMMINGBIRDS.—The fol- for the study of structural adaptations in other lowing muscles, present in at least some oscines, parts of the body as well, and we anticipate that are lacking in hummingbirds: adductor mandi- these adaptive complexes will have systematic bulae externus, pars caudalis; adductor mandi- significance at various taxonomic levels. bulae externus, pars rostralis lateralis (some spe- Literature Cited

Baumel, J.J., A.S. King, A.M. Lucas, J.E. Breazile, and H.E. Cypselidae.y

45 46 SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY

Moller, Walter the Feeding Apparatus in the Hawaiian Honey- 1931. Uber die Schnabel-und Zungenmechanik bliiten- creeper Genus Loxops (Drepanididae). Ornithologi- besuchender Vogel, I: Ein Beitrag zur Biologie des cal Monographs, American Ornithologists' Union, 15: vii Blumenvogels. Biologia Generalis, 6:651-723, 36 fig- + 173 pages, 14 figures, 26 plates. ures. Richardson, Frank Morioka, Hiroyuki 1972. Accessory Pygostyle Bones of Falconidae. Condor, 1974. Jaw Musculature of Swifts (Aves, Apodidae). Bul- 74(3): 350-351. letin of the National Science Museum of Tokyo, 17(1): Scharnke, Hans 16 pages, 8 figures. 1931. Beitrage zur Morphologie und Entwicklungsges- Newton, Alfred chichte der Zunge der Trochilidae, Meliphagidae, 1893-96. A Dictionary of Birds. 1088 pages. London: und Picidae. Journal fur Ornithologie, 79(4):425-491, Adam and Charles Black. 54 figures. Palmgren, Pontus Shulfeldt, Robert W. 1949. Zur biologischen Anatomie der Halsmuskulatur 1890. Myology of the Raven (Corvus corax sinuatus), A Guide der Singvogel. In E. Mayr and E. Schuz, editors, to the Study of the Muscular System in Birds, xix + 343 Ornithologie als Biologische Wissenschaft, pages 192- 203. Heidelberg: Car! Winter. pages, 76 figures. London: MacMillan and Co. Raikow, Robert J. Weymouth, Robert D., R.C. Lasiewski, and A.J. Berger 1976. Pelvic Appendage Myology of the Hawaiian 1964. The Tongue Apparatus in Hummingbirds. Ada Honeycreepers (Drepanididae). Auk, 93(4): 774- Anatomica, 58:252-270, 10 figures. 792, 4 figures, 1 table. Zusi, Richard L. 1977. Pectoral Appendage Myology of the Hawaiian 1962. Structural Adaptations of the Head and Neck in Honeycreepers (Drepanididae). Auk, 94(2):331- the Black Skimmer, Ryncops nigra Linnaeus. Publi- 342, 5 figures, 1 table. cations of the Nuttall Ornithological Club, 3: viii 4- 101 1978. Appendicular Myology and Relationships of the pages, 44 figures. New World Nine-Primaried Oscines (Aves: Pas- Zusi, Richard L., and Gregory Dean Bentz seriformes). Bulletin of the Carnegie Museum of Natural 1982. Variation of a Muscle in Hummingbirds and History, 7: 43 pages, 10 figures, 5 tables. Swifts and Its Systematic Implications. Proceedings Richards, Lawrence P., and Walter J. Bock of the Biological Society of Washington, 95(2) :412-420, 1973. Functional Anatomy and Adaptive Evolution of 2 figures. Appendix 1 Index to Muscle Abbreviations The following list includes all muscle abbreviations used in figures in this paper. In addition, we have included abbreviations for muscles not present in hummingbirds or not illustrated here as a possible standard for future workers on avian myology. The muscle names are taken mainly from Baumel et al., 1979. This list may also prove useful to anyone using abbreviations for muscle names other than these to prevent duplication of abbreviations.

ABA abductor alulae COG constrictor glottidis ABD2 abductor digiti II COL columellae AB D4 abductor digiti IV CSP costoseptalis AB DM abductor digiti majoris CST costosternalis ADA adductor alulae CSTMA costosternalis, pars major ADD 2 adductor digiti II CST MI costosternalis, pars minor ADR adductor rectricium CT cleidotrachealis AMC adductor manidibulae caudalis DC depressor caudae AME adductor manidibulae externus DG dilator glottidis adductor mandibulae externus, pars cau- DM depressor mandibulae AMEC dalis DMA deltoideus major adductor mandibulae externus, pars ros- AMER DMI deltoideus minor tralis DPV depressor palpebrae ventralis adductor mandibulae externus, pars ros- EB A extensor brevis alulae AMERL tralis lateralis EBD3 extensor brevis digiti III adductor mandibulae externus, pars ros- EBD4 extensor brevis digiti IV AMERM tralis medialis EC ectepicondylo-ulnaris adductor mandibulae externus, pars ros- EDC extensor digitorum communis AMERT tralis temporalis EDL extensor digitorum longus adductor mandibulae externus, pars ven- AME V tralis EHL extensor hallucis longus EHLD extensor hallucis longus, pars distalis B brachialis EHLP extensor hallucis longus, pars proximalis BB biceps brachii ELA extensor longus alulae BC biventer cervicis ELDM extensor longus digiti majoris BM branchiomandibularis EMR extensor metacarpi radialis BR bulbi rectricium EMU extensor metacarpi ulnaris C complexus EN entepicondylo-ulnaris CA cervicalis ascendens EPD3 extensor proprius digiti III CC cucullaris capitis ES expansor secundariorum CCA coracobrachialis caudalis FA flexor alulae CCEC cucullaris cervicis, pars clavicularis FB fibularis brevis CCI cucullaris capitis, pars interscapularis FCL flexor colli lateralis CCPR cucullaris capitis, pars propatagialis FCM flexor colli medialis CCR coracobrachialis cranialis FCR L flexor cruris lateralis CF caudofemoralis FCR LA flexor cruris lateralis, pars accessoria CG ceratoglossus FCR LP flexor cruris lateralis, pars pelvica CH cricohyoideus FCRM flexor cruris medialis COCI constrictor colli, pars intermandibularis FC U flexor carpi ulnaris 47 48 SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY

FDL flexor digitorum longus LEC levator caudae FDM flexor digiti minoris LPD levator palpebrae dorsalis FDP flexor digitorum profundus M mesoglossus FDS flexor digitorum superficialis FH B flexor hallucis brevis OD obliquus dorsalis FHL flexor hallucis longus OE A obliquus externus abdominus FL fibularis longus OI A obliquus internus abdominus FPD2 flexor perforatus digiti II OL obturatorius lateralis FPD3 flexor perforatus digiti III OLD obturatorius lateralis, pars dorsalis FPD4 flexor perforatus digiti IV OLV obturatorius lateralis, pars ventralis FPPD2 flexor perforans et perforatus digiti II OM obturatorius medialis FPPD3 flexor perforans et perforatus digiti III O V obliquus ventralis FTE femorotibialis externus P pectoralis FTI femorotibialis internus PE pubocaudalis externus FTM femorotibialis medius PI pubocaudalis internus G gastrocnemius PIF pubo-ischio-femoralis GG genioglossus PL plantaris GI gastrocnemius, pars intermedia PM N pyramidalis membrane nictitantis GL gastrocnemius, pars lateralis PO popliteus GM gastrocnemius, pars medial is PPB pectoralis, pars propatagialis brevis PPL pectoralis, pars propatagialis longus HGO hypoglossus obliquus PPQ protractor pterygoidei et quadrat i HGR hypoglossus rostral is PRP pronator profundus IC intercristales PRS pronator superficialis ICB interceratobranchialis PS pectoralis subcutanea ICR iliotibialis cranialis PSA pectoralis subcutanea, pars abdominalis ID interosseus dorsal is PSP pseudotemporalis profundus IE intercostales externi PSS pseudotemporalis superficialis IF iliofibularis PST pectoralis subcutanea, pars thoracica IFE iliofemoralis externus PT pterygoideus IF I iliofemoralis internus PTDL pterygoideus, pars dorsalis lateralis II intercostales interni PTDM pterygoideus, pars dorsalis medialis IL iliotibialis lateralis PTR pterygoideus, pars retractor ILC iliocostalis PTVL pterygoideus, pars ventralis lateralis IM intermandibularis PTVM pterygoideus, pars ventralis medialis IN inclusi PTVME pterygoideus, pars ventralis medialis, eusta ISF ischiofemoralis chian slip IT intertransversarii QMN ITCA iliotrochantericus caudalis quadratus membrane nictitantis ITCR iliotrochantericus cranialis R A rectus abdominus ITM iliotrochantericus medius R CD rectus capitis dorsalis IV interosseus ventralis RCL rectus capitis lateralis L lumbricalis RC V rectus capitis ventralis LAC lateralis caudae RC VL rectus capitis ventralis, pars lateralis LCD longus colli dorsalis RC VM rectus capitis ventralis, pars medialis LC DCA longus colli dorsalis, pars caudalis RD rectus dorsalis LCDCR longus colli dorsalis, pars cranialis R L rectus lateralis LCDP longus colli dorsalis profundus R M rectus medialis LC DT longus colli dorsalis thoracica R P rhomboideus profundus LCL levator cloacae R S rhomboideus superficialis LCO levatores costarum R V rectus ventralis LC V longus colli ventralis S scalenus LD latissimus dorsi SBC subcoracoideus LDCA latissimus dorsi, pars caudalis SBS subscapularis LDCR latissimus dorsi. pars cranialis SBSL subscapularis caput laterale NUMBER 385 49

SBSM subscapularis caput mediale TAB transversus abdominus SC sternocoracoideus TAS thoracicus ascendens SCA splenius capitis TB triceps brachii SCL sphincter cloacae TBB tracheobronchialis brevis SD syringealis dorsalis TBD tracheobronchialis dorsalis SE serpihyoideus TB V tracheobronchialis ventralis SHCA scapulohumeralis caudalis TC transversus cloacae SHCR scapulohumeralis cranialis TCR tibialis cranialis SOL syringealis obliquus lateralis TH humerotriceps SOV syringealis obliquus ventralis TL tracheolateralis SP serratus profundus TP tensor propatagialis ss serratus superflcialis TPB tensor propatagialis, pars brevis SSCA serratus superflcialis, pars caudalis TPE tensor periorbitae SSCR serratus superflcialis, pars cranialis TPL tensor propatagialis, pars longa SSM serratus superficialis, pars metapatagialis TS scapulotriceps ST stylohyoideus STH sternohyoideus UD ulnometacarpalis dorsalis STT sternot racheal is U V ulnometacarpalis ventralis SU supinator SUP su pracoracoi deus VD vocal is dorsalis S V syringealis ventralis V V vocalis ventralis Appendix 2 Index to Abbreviations, Excluding Muscles The following abbreviations appear in italics in the figures to distinguish them from abbreviations for muscle names.

A atlas HS horizontal septum A P alular phalanx HU humerus AX axis HY hypotarsus BC bicipital crest of humerus IFL iliofibular loop BCA basibranchiale caudale IL ilium BCD bicipital crest, dorsal head IRL interosseal radioulnar ligament BCR basibranchiale craniale IS ischium BC V bicipital crest, ventral head JB jugal bar BP blade of pygostyle lateral jugomandibular ligament BTP basitemporal plate LJL B V body of vertebra LS ligamentous sling LSL long sternocoracoidal ligament CA carpometacarpus CAP carotid process M mandible CAP caudal articular process MET metatarsus CB coracoidal bar MF mandibular fenestra CE ceratobranchiale MI D minor digit CL clavicle MJL medial jugomandibular ligament CLO cloaca MN mandibular nerve CLP craniolateral process of sternum MPM medial process of mandible CO coracoid MR mandibular ramus CP cerebellar prominence NF nasal flange CPH head of costal process OB oval bone cs costal spine OL occipitomandibular ligament DB dorsal bar of upper jaw ON optic nerve DC deltoid crest OPF optic foramen DE dorsal epicondyle ORF orbital fonticulus DP dorsal process PB prepalatine bar D PA dorsal process of axis PEMR process of M. extensor metacarpi radialis D P MA distal phalanx, major digit PL postorbital ligament EN entoglossum PP MA proximal phalanx, major digit EO ear opening PT pterygoid EP epibranchiale PU pubis EP ectethmoid plate PY pygostyle FE femur QU quadrate FI Fibula RA radius GC glenoid cartilage RE rect rices GO N groove of olfactory nerve RMN ramus of mandibular nerve HA hallux RPM retroarticular process of mandible H B humerocarpal band SC scapula H HU head of humerus SM sternocoracoclavicular membrane HP humeroulnar pulley SP spinous process 50 NUMBER 385 51

S R sternal rib UG uropygial gland S T P synsacral transverse process UL ulna T C tibial cartilage ULMB ulnar-manus band 77 tibiotarsus ULP ulnar patella TNC transverse nuchal crest UP uncinate process T P E tympanic process of exoccipital V A vertebral arch T PI tendon of M. pubocaudalis internus V B ventral bar of the upper jaw T PIL terminal process of the ilium VCL ventral collateral ligament TP P transpalatine process V E ventral epicondyle T PR S tubercle of M. pronator superficialis V P ventral process 77? C triosseal canal V R vertebral rib T R L transverse radioulnar ligament WPT wall of the palatine trough 77? P transverse process T TPB tubercle of M. tensor propatagialis, pars brevis ZP zygomatic process 52 SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY Figures 1-20 (Abbreviations identified in Appendices)

0 D R M R D

OP F R L OR F T N C

R M

0 D

R L E P T PE 0 V 0 V E 0 QU a

R D O D

R M Q M N

ON PM

R L

0 V R V

FIGURE 1.—Muscles of eye, Eulampis jugularis: a, areas of origin on skull; b, muscles with left eye removed; c, muscles of nictitating membrane of right eye in posteromedial view. NUMBER 385 53

C C

P P Q AMERT 6 O N

J B

a

M N

FIGURE 2.—Muscles of jaws, Eulampis jugularis: a, superficial muscles in left lateral view; b, muscles of quadrate; c, rostrodorsolateral view of muscles of orbit. 54 SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY

PB TP P WPT PT V M E PT BT P

R C D a RC V

0 M

PS P

AMER AMEV AMC

M F PT V L Z P

FIGURE 3.—Muscles of jaws, Eulampis jugularis: a, ventral view; b, left dorsolateral view with eye, ectethmoid, jugal bar, adductor muscles, and M. pseudotemporalis profundus removed; c, dorsal view of caudal end of left ramus of lower jaw showing areas of muscle attachment in black. HG R HG 0 CG ST ICB

EN B CR B CA

FIGURE 4.—Muscles of tongue and hyoid apparatus, Eulampis jugularis: a, ventral view, right branchiomandibularis removed; b, form of M. serpihyoideus found in some other genera; c, dorsal view of skull, left branchiomandibularis removed; d, ventral view of hyoid muscles; e, enlarged ventral view of tongue muscles; /, dorsal view of hyoid muscles; g, left lateral view of hyoid muscles. 56 SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY

C P

F C L FCM L C V

FIGURE 5.—Muscles of neck, Eulampis jugularis: a, left lateral view of superficial muscles; b, caudal view of deep, dorsal muscles to cranium; c, left lateral view of middle layer of neck section I; d, ventral muscles of cranium and neck section I; e, left lateral view of deep muscles of cranium and neck section I. NUMBER 385 57

NECK SECTIONS

I n in

""• • »•

•< ^ S P

V P a

FIGURE 6.—Diagram of slips of M. longus colli ventralis, Eulampis jugularis in left lateral view: a, longer slips; b, shorter slips. 58 SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY

C A D P A

L C D CA a

TR P

FIGURE 7.—Muscles of neck, Eulampis jugularis: a, dorsal view of deep muscles of cranial portion of neck; b, left lateral view of muscles between vertebrae 6 and 7; c, left lateral view of deep muscles to vertebra 6; d, ventral view of muscles between vertebrae 6 and 7, with M. longus colli ventralis removed; e, dorsal view of muscles between vertebrae 6 and 7, with M. longus colli dorsalis and M. cervicalis ascendens removed. NUMBER 385 59

II T AS L C DT ILC LCO CA IT

H S

S R

"CL P

CST MA

FIGURE 8.—Muscles of trunk, Eulampis jugularis: a, right dorsolateral view of vertebral muscles; b, right lateral view of trunk and abdomen; c, right lateral view of deeper muscles of ribs; d, left medial view of muscles of ribs. 60 SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY

P E LA C LE C T P IL RE

FIGURE 9.—Muscles of tail, Eulampis jugularis: a, dorsal view with uropygial glands and some muscles of left side removed; b, right lateral view; c, right lateral view with M. transversus cloacae cut and reflected, and M. pubocaudalis externus (dashed line) removed; d, ventral view; e, ventral view of right rectricial bulb. NUMBER 385 61

SH CR RS LDCR L D CA SP R

SC

CO

T P B EM R E DC C CA FIGURE 10.—Muscles of shoulder and humerus, Eulampis jugularis: a, dorsal view of left side; b, caudal view of left humerus with some muscles removed or cut and displaced; c, dorsal view of deeper muscles of left shoulder; d, lateral view of left shoulder with some muscles cut and removed; e, like d with more muscles removed and M. pectoralis raised; /, left lateral view of deep muscles to bicipital crest of humerus. 62 SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY

CL SBS RS SSCR RPSP P S T

S M

SBC LSL CO C CA

FIGURE 11 (above).—Axillary muscles of Eulampis jugularis, ventromedial view of isolated right pectoral girdle, with M. coracobrachialis caudalis displaced.

FIGURE 12 (upper right).—Major flight muscles, Eulampis jugularis: a, right lateral view of superficial muscles; b, same view of deeper muscles, with right wing raised. SUP SC R S SH CR

D Ml

FIGURE 13 (lower right).—Deep muscles of shoulder, Eulampis jugularis, left side, dorsal view. C CR

D MA HU NUMBER 385 63

PR S PR P 1

EMR

AB A

E S VCL FCU

FIGURE 14.—Muscles of left wing, Eulampis jugularis: a, superficial muscles, ventral view; b, deep muscles, ventral view; c, superficial muscles, dorsal view; d, deep muscles, dorsal view. (Numbers 1-4 refer to ligamentous loops discussed in text.) 64 SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY

H HU

V E a FIGURE 15.—Left humerus showing attachments of muscles and ligaments, Eulampis jugularis: a, caudal view; b, cranial view.

DP MA ID ELDM. P P MA EDC ULMB ABDM AP ADA

a

PR P U V F D P HB

FIGURE 16.—Muscles of left manus, Eulampis jugularis: a, dorsal view; b, ventral view. (Numbers 1 and 5-7 refer to Hgamentous or bony loops discussed in text.) NUMBER 385 65

IT CA IT CR UG IF

F B FPD3 FPD4 FPPD3 FPPD2 T CR IF L

FT E

HY Tl G FPD4

T CR FB FDL FPD2 EDL FPPD2 FPPD3 T CR FIGURE 17.—Muscles of right hindlimb, Eulampis jugularis in lateral view: a, superficial muscles; b, deep thigh muscles and middle layer of crus; c, deep muscles of crus. (Number 8 refers to ligamentous loop discussed in text.) 66 SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY

OM

FDL GM Gl TCR

Tl T CR

FIGURE 18.—Muscles of right hindlimb, Eulampis jugularis in medial view: a, superficial muscles; b, deep muscles. (Number 8 refers to ligamentous loop discussed in text.) NUMBER 385 67

EDL

a

FDL FHL

FPD2 FPPD3 FPD 3 FPPD 2 FPD4

-FHL

FDL

FIGURE 19.—Tendons on ventral surface of right foot, Eulam- pis jugularis: a, proximal end of tarsometatarsus; b, cross section of tibial cartilage; c, relations of major flexor tendons. 68 SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY

T CR

FDL

EDL AD D 2 FPD4 FDL EDL

FIGURE 20.—Muscles of right foot, Eulampis jugularis: a, superficial muscles, medial view; b, deep muscles, medial view; c, superficial muscles, lateral view; d, tendons of the digits in cranioven- tromedial view; e, deep tendons of the digits. (Some tendons shown in black or cross-hatched for clarity. Number 9 refers to ligamentous loop discussed in text.) Index to Main Muscle Headings abductor alulae, 32 flexor cruris medialis, 35 longus colli ventralis, 14 abductor digiti majoris, 32 flexor digiti minoris, 33 obliquus dorsalis, 3 adductor alulae, 32 flexor digitorum longus, 39 obliquus externus abdominus, 19 adductor digiti II, 40 flexor digitorum profundus, 29 obliquus internus abdominus, 21 adductor mandibulae caudalis, 6 flexor digitorum superficialis, 29 obliquus ventralis, 3 adductor manibulae externus, 4 flexor hallucis brevis, 39 obturatorius lateralis, 35 biceps brachii, 27 flexor hallucis longus, 38 obturatorius medialis, 35 biventer cervicis, 12 flexor perforans et perforatus digiti II, pectoral is, 25 brachialis, 28 37 pectoralis subcutanea, 40 branchiomandibularis, 10 flexor perforans et perforatus digiti III, plantaris, 38 bulbi rectricium, 21 37 flexor perforatus digiti II, 38 pronator profundus, 29 caudofemoralis, 35 flexor perforatus digiti III, 38 pronator superficialis, 28 ceratoglossus, 11 flexor perforatus digiti IV, 38 protractor pterygoidei et quadrati, 7 cervical is ascendens, 15 pseudotemporalis profundus, 6 complexus, 12 gastrocnemius, 36 pseudotemporalis superficialis, 6 constrictor colli, pars intermandibu- genioglossus, 9 pterygoideus, pars dorsalis medialis, 8 laris, 41 hypoglossus obliquus, 11 pterygoideus, pars ventralis lateralis, coracobrachialis caudalis, 25 hypoglossus rostralis, 11 7 coracobrachialis cranialis, 25 pterygoideus, pars ventralis medialis, iliocostalis, 17 costoseptalis, 20 7 iliofemoralis externus, 36 costosternalis, 20 pubocaudalis externus, 22 iliofemoralis internus, 36 cucullaris capitis, 40 pubocaudalis internus, 22 iliofibularis, 34 cucullaris cervicis, pars clavicularis, 41 pubo-ischio-femoralis, 35 iliotibialis cranialis, 33 pyramidalis membranae nictitantis, 4 deltoideus major, 27 iliotibialis lateralis, 33 deltoideus minor, 27 iliotrochanterici, 33 quadratus membranae nictitantis, 4 depressor caudae, 21 iliotrochantericus caudalis, 33 rectus abdominus, 20 depressor mandibulae, 8 iliotrochantericus cranialis, 33 rectus capitis dorsalis, 13 ectepicondylo-ulnaris, 31 iliotrochantericus medius, 34 rectus capitis lateralis, 13 extensor digitorum communis, 30 inclusi, 16 rectus capitis ventralis, 13 extensor digitorum longus, 37 interceratobranchialis, 11 rectus dorsalis, 3 extensor hallucis longus, 39 intercostales externi, 19 rectus lateralis, 3 extensor longus alulae, 31 intercostales interni, 20 rectus medialis, 3 extensor longus digiti majoris, 31 intercristales, 13 rectus ventralis, 3 extensor metacarpi radialis, 30 intermandibularis, 9 rhomboideus profundus, 24 extensor metacarpi ulnaris, 30 interosseus dorsalis, 32 rhomboideus superficialis, 23 expansor secundariorum, 28 interosseus ventralis, 32 scalenus, 19 intertransversarii, 16 scapulohumeralis caudalis, 24 femorotibiales, 34 ischiofemoralis, 35 femorotibialis externus, 34 scapulohumeralis cranialis, 24 femorotibialis internus, 34 lateralis caudae, 21 serpihyoideus, 9 femorotibialis medius, 34 latissimus dorsi, 23 serrati, 24 fibularis brevis, 37 levator caudae, 21 serratus profundus. 24 fibularis longus, 36 levator cloacae, 23 serratus superficialis, 24 flexor carpi ulnaris, 29 levatores costarum, 19 serratus superficialis. pars metapata- flexor colli lateralis, 13 longissimus dorsi, 17 gialis, 41 flexor colli medialis, 14 longus colli dorsalis, pars caudalis, 15 sphincter cloacae. 23 flexor cruris lateralis, pars pelvica and longus colli dorsalis, pars cranialis, 15 splenius capitis, 12 pars accessoria, 34 longus colli dorsalis thoracica, 18 sternocoracoideus, 26

69 70 SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY

stylohyoideus, 10 supracoracoideus, 26 transversus cloacae, 22 subcoracoideus, 25 tensor propatagialis, 26 triceps brachii, 28 subcoracoscapulares, 25 thoracicus ascendens, 18 ulnometacarpalis dorsalis, 32 subscapularis, 25 tibialis cranialis, 36 ulnometacarpalis ventralis, 31 supinator, 31 transversus abdominus, 20

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