New Pleurotomariid Gastropods from the Western Atlantic, with A

BULLETIN OF MARINE SCIENCE

VOLUME 15 1965 NUMBER 4

NE\V PLEUROTOlVIARIID GASTROPODS FROM THE \VESTERN ATLANTIC, vVITH A SUMMARY OF THE RECENT SPECIES' FREDERICK M. BAYER ImtitU/e of Marine Science, University of Miami

ABSTRACT Three new species of pleurotomariid gastropods from the Western Atlantic, Perotrochus midas, P. lucaya, and P. gemma, are described and figured. All previously known Recent species of the family are reviewed briefly and illustrated. The type specimens of Perotrochus quoyanus, P. teramachii, and Entemnotrochus rumphii are figured. The generic groups are discussed and defined.

INTRODUCTION Owing to their long geological history and comparatively recent discovery in the living state, their striking appearance, and their general rarity, perhaps no mollusks have attracted more concentrated interest on the part of both scientists and laymen than have the pleurotomarians. The surviving family, Pleurotomariidae, extends back in geological time to the beginning of the Mesozoic, and related extinct families carry the line back to the Cambrian. The discovery, in 1856, of the first living representative of a predominantly Paleozoic family naturally excited much interest. During the ensuing 48 years, five more species were discovered, three in Japan, one in the East Indies, and another in the West Indies. For many years, each new specimen elicited individual attention. Bouvier & Fischer (1899) reviewed all the reported examples of the four species known up to that time. After the publication of Pleurotomaria hirasei by Pilsbry in 1903, no further new species of pleurotomarians were discovered for 45 years, tending to corroborate the idea, supported by Lindholm (1927), that the survivors of this once numerous group are few in number of species and rare in individuals, indicating the approach of total extinction. Then, in 1948, Tomlin announced the discovery of a seventh species, in South African waters far from all previously known habitats of living pleurotomarians. This was followed, in 1955, by Kuroda's report of a new species

IContribution No. 651 from the Institute of Marine Science, University of Miami. This paper is one of a series resulting from the National Geographic Society-University of Miami Deep-Sea Biology Program. Some of the material reported herein was obtained during deep-water ope rat ions of R IV G ERDA supported by grant G B-1204 from the National Science Foundation. 738 Bulletin of Marine Science \15(4) from Japan, Perotrochus teramachii, the indications by Kira (1961) and Habe (1962) of still another species (misidentified as P. teramachii) from Japan, and the description of Mikadotrochus schmalzi by Shikama (1961). The number of described West Indian species remained unchanged, however, for nearly 100 years. Then, on June 21, 1963, the research vessel GERDA,of the Institute of Marine Science, University of Miami, while trawling off Sombrero Light in the Florida Keys, obtained a handsome pleurotomariid which at first glance was thought to be Perotrochus quoyanus because of its comparatively small size and shallow slit. Examination in the laboratory immediately revealed that it was not P. quoyanus as originally believed. Comparison with specimens of the various species in the collections of the U.S. National Museum confirmed that it represented an undescribed species, which subsequently was described under the name Mikadotroehus amabilis (Bayer, 1963), the third pleurotomarian species known from the Western Atlantic Ocean. Continued operations of R/V GERDA failed to reveal any further pleurotomarian material until March 1965, when a haul off Grand Bahama Island produced two large fragments of Entemnotrochus adansonianus (Crosse & Fischer). On the assumption that such fragments indicated the presence of a living population nearby, intensive exploration of the area was planned for the first opportunity. This came in July 1965, when R/V GERDAduring cruise G-6528 worked northward in the Straits of Florida to approximately 27°30'N., then around the northwestern extremity of Little Bahama Bank, and finally into Northwest Providence Channel. Dredging and trawling was undertaken in the general area where fragments of adansonianus had been found in March. During three days of operation (July 20, 21 and 22), three species of pleurotomarians were obtained, two of them new, constituting one of the most important biological finds made aboard the GERDA. In the course of reviewing pleurotomarian material for this report, a number of museum specimens from Western Atlantic localities were examined, among them two Perotrochus from Barbados, loaned by the Academy of Natural Sciences of Philadelphia, through the kindness of Dr. R. Tucker Abbott. These proved to be different from the type of Perotrochus quoyanus and from the specimens trawled by R/V GERDA, and are here treated as a third new species. Accordingly, six pleurotomarian species are now known to occur in the Western Atlantic. ACKNOWLEDGMENTS The specimens that stimulated the preparation of this paper were obtained during deep-water biological operations co nd u cte d aboard R/V GERDAof the Institute of Marine Science, University of Miami. To Captain William Dickinson and the crew of R/V GERDA, and to the scientific personnel of cruise G-6528, consisting of Martin Roessler (party 1965 J Bayer: Pleurotomariid Gastropods 739 chief), Dr. Donald F. Squires (visiting scientist), Jon C. Staiger, R. H. Chesher, R. J. Livingston, D. G. Smith, and Koesoebiono (biologists), 1 express sincere appreciation for a highly successful cruise. I am no less grateful to Dr. Joseph Rosewater, Curator of Mollusks at the U.S. National Museum, who made available the facilities of his laboratory; to Mr. W. J. Byas, of the U.S. National Museum, who extracted the soft parts of the pleurotomarians for dissection; to Dr. R. Tucker Abbott of the Philadelphia Academy, and to Mr. John Finlay, who made available to me the specimens from Barbados here described as new; to Drs. William J. Clench and Ruth D. Turner of the Museum of Comparative Zoology, who provided specimens and photographs from their collections; to Professor Tokubei Kuroda of Kyoto University, who provided photographs of Entemnotrochus rumphii, Perotrochus teramachii, and Mikadotrochus schmalzi; to Dr. A. W. Janssen of the Natuurhistorisch Museum, Rotterdam, who provided photographs of the type specimen of E. rumphii; and to my colleagues at the Institute of Marine Science who have unfailingly extended to me the benefit of their knowledge and experience. The biological operations of R/V GERDAhave been supported by the National Science Foundation through grant GB-1204 and the research has been supported by the National Geographic Society through a most generous grant for investigations of deep-sea biology. The assistance of both of these agencies is gratefully acknowledged. The publication of the colored figures of Perotrochus midas contained in this paper was made possible by the International Oceanographic Foun- dation through a grant to defray part of the printing costs. Family PLEUROTOMARIIDAESwainson, 1840 As recognized by Knight et al. (1960: 219), this family includes eleven genera, of which three contain Recent species: Entemnotrochus P. Fischer, 1885; Perotrochus P. Fischer, 1885; and Mikadotrochus Lindholm, 1927. The type-genus, Pleurotomaria Defrance, 1826, is extinct, ranging in time from Lower Jurassic to Lower Cretaceous. The differences separating these taxa appear to be of a rather superficial nature and might have been considered less important in any group not subjected to the close scrutiny that the Recent pleurotomariids have attracted. However, it does appear that no species with the nodose sculpture of typical Pleurotomaria has lived since the Lower Cretaceous, and possibly this is adequate justification for treating the Recent forms as generically distinct. SYSTEMATICCHARACTERS The usual conspicuous features of the shells form the chief basis for the separation of pleurotomarian species. Among these are size, shape, depth and location of slit, sculpture, and color, most of which have never been expressed in any really objective manner. A major difficulty, not soon to 740 Bulletin of Marine Science 115(4) be overcome, is the very small number of specimens available for study. No meaningful evaluation of the reliability of morphological characters can be expected until a substantial number of specimens can be obtained. The significance of this problem can be suggested by pointing out that one of the largest collections in the world, that of the United States National Museum, contains only 13 specimens representing 7 species, viz.: adansonianus (1), africanus (I), amabilis (1), beyrichii (1), hirasei (4), quoyanus (4), and salmianus (1). Following the publication of this paper, those numbers will increase by one specimen each of two new species described herein. Only one species of pleurotomarian is well represented in collections, Perotrochus hirasei (Pilsbry) from Japan. The various specimens show minor differences but on the whole are reasonably constant as to size, shape, sculpture and color. Small individuals are clearly recognizable specifically and easily separated from other species living in the same region. The known specimens of P. amabilis, M. beyrichii, E. adansonianus and E. rumphii are similarly consistent but the number of specimens from which to draw conclusions is extremely limited. Size.- The maximum size attained by each species is characteristic, but the value of this character fails in a unique specimen. Both species of Entemnotrochus are known to reach a very large size, whereas all species of Perotrochus so far described are smaller. However, within the latter genus is a group of species reaching moderately large size (amabilis, africanus, hirasei, midas n.sp., teramachii, which range from 75-120 mm in diameter), but never the dimensions of fully grown specimens of Entemnotrochus rumphii and adansonianus. Shape.- The shape of the sheIl seems to be quite constant in the commoner forms, and even in the rarer ones, such as E. rumphii and P. amabilis (three specimens reported of each), the shells correspond rather closely. The slope of the spire, the degree of inflation of the whorls (and its consequent effect on the depth of the sutures), and the shape of the aperture vary only within rather narrow limits, although these have never been established on objective grounds. The strong sigmoid flexure of the columellar lip, used by Lindholm ( 1927) as a distinguishing character of his new subgenus Mikadotrochus, is present to some degree in alI species of Perotrochus although its development is greatest in heavy-shelled forms such as those he placed in the new subgenus. The depth of the marginal slit is constant within genera, being deepest in Entemnotrochus, shaIlowest in Mikadotrochus, and intermediate in Perotrochus. The position of the slit on the whorl is a generic level character. It is above mid-whorl in species of Entemnotrochus, mid-whorl or below in all others. In the large, thin-shelled species such as africanus, 1965J Bayer: PJeurolomariid Gastropods 741 midas n. sp., and teramachii, the slit is placed somewhat closer to mid- whorl than in the smaller or more solid forms such as amabilis, gemma n. sp., Jucaya n. sp., and quoyanus. An exception is P. hirasei, a large, heavy-shelled species with the slit in the low position. ScuJpture.-Among the gastropods there are many well known examples of sculptural characters with systematic value, just as there are cases in which sculptural characters have only general significance. In such groups as the muricids, sculptural features are important at the specific level, the generic level, or both. In the pleurotomarians, sculpture is of a very uniform type but nevertheless it differs visibly-and, presumably, measur- ably-among the various species. Therefore, it is not unreasonable to think that some method can be devised to make use of sculptural characters as a systematic aid in this group. Fundamentally, the sculpture of pleurotomarians consists of so-called axial (i.e., "collabral") riblets formed periodically at the apertural margin during pauses in growth of the shell, roughly equidistant spiral riblets following the direction of the whorls, and the shallow spiral groove or band (the fasciole, slit-band, cicatrix or selenizone) following the whorls at roughly mid-point between suture and periphery and terminating in the deep marginal slit. The axial riblets are a reflection of growth, and their spacing therefore may gradually change during development of the shell, as well as locally in response to temporary differences in growth rate. The spiral riblets begin to appear in the first or second whorl of the teleoconch. They may increase in number either by dichotomy (i.e., by progressively widening, eventually splitting into two) or by intercalation (minute new riblets appearing in the interspaces between the older ones). TIle intersection of the axial growth riblets and the spiral riblets (or cords) produces a somewhat cancellated appearance more or less modified by the formation of small, raised beads at the points of intersection. Depending upon which sculptural element is stronger, the beads may be either rounded or more or less elongated in one direction or the other. In one specimen (the small shell from Bermuda, tentatively identified as quoyanus), the spiral and axial riblets are scarcely raised and only the beads at the intersections stand up conspicuously from a smooth surface. The regularity of sculpture in Perotrochus together with its characteristic appearance in the various species leads to the supposition that sculptural characters could have systematic value if properly analyzed. To explore this possibility, I have determined the number of spiral cords and the frequency of axial riblets and expressed them graphically in several ways for a few species. As these features are correlated with growth and shell size and leave a permanent record, they can be observed at progressive stages in the development of a single shell. The results, while not based upon a signifi- 742 Bulletin of Marine Science [15(4) cant sample, show that it may be possible to draw certain generalities. When ample material becomes available, meristic counts of sculptural features may prove to be valuable taxonomic aids. C%r.-In most pleurotomarian species, the outer surface of the shell is more or less brightly colored with streaks and blotches of rusty red, orange, yellow, or ochre on a paler ground, while the interior is brilliantly iridescent. The outer porcellaneous layer containing the pigment may be milky and opaque as in M. beyrichii, P. hirasei, P. quoyanus, and P. amabilis, or thin and translucent, allowing the iridescence of the nacreous layer to show through, as in P. midas n. sp., and evidently P. teramachii. Shells of the latter type have a striking metallic luster and are perhaps the most beautiful of all pleurotomarians. Color seems relatively constant in any given species, although some variation in hue does occur. The markings of P. hirasei are always very similar but the shade of red and amount of streaking with white varies. All specimens of P. quoyanus are pale, with very faint brownish streaks, whereas amabilis is more intensely colored. Thus, it is reasonable to conclude that the general nature of the color pattern is systematically valid but that small variations in hue have no significance. MEASUREMENTSANDTERMINOLOGY The shell measurements employed in this paper were taken in the fashion outlined by Cox (1960: 126-128), and as shown in Figure 1. Apparent inconsistencies in method of measuring the depth of the slit were necessitated by broken margins in some specimens. Sculptural features such as the beaded spiral cords and axial riblets were counted in standard distances (1 cm, and one-tenth of the circumference of the whorl) and at specified sites. The spiral cords were counted (1) from the slit (or fasciole) to the suture, (2) from slit or fasciole to the periphery (or the suture below), and (3) from periphery to the umbilical callus. The number of ribs on the fasciole were counted in the region just behind the slit on the body whorl, and then in a region directly above this on the preceding whorl. The raised margins of the fasciole are not counted either as ribs of the fasciole or as part of the spiral sculpture proper. The highly specialized terms employed by Knight et al. (1960) in the Treatise on Invertebrate Paleontology, and by paleontologists generally, are for the most part avoided when the meaning of more familiar terms is sufficiently clear. ANATOMICALFEATURES As in the case of the first pleurotomarian collected by biologists of the Institute of Marine Science, the soft parts of the two new species, P. midas and P. lucaya, most recently taken bv R/V GERDAhave been submitted to Dr. Vera Fretter for examination. Her findings will form the subject of a separate paper. 1965] Bayer: Pleurotomariid Gastropods 743

CLASSTFICA nON OF THE RECENT SPECIES Among the living species, those with a large, openly umbilicate shell with a very deep slit situated above mid-whorl and sculpture becoming obscure on the later whorls stand apart from those with an excavate but not umbilicate base and a short slit situated mid-whorl or lower. P. Fischer (1885) assigned the former to a special section Entemnotrochus, with Pleurotomaria adansoniana Crosse & Fischer as its type, and the latter to section Perotrochus with Pleurotomaria quoyana Fischer & Bernardi as type-species. Lindholm (1927) separated P. beyrichii Hilgendorf from Perotrochus because of its large, heavy shell with a thick, sigmoidally bent columellar lip and proposed for it the new subgenus Mikadotrochus. At the time of his revision, Lindholm (1927: 411-412) separated the subgenera according to the following not-quite-dichotomous key (translated from Russian by Wayne Bock), which utilized gross morphological features as well as characters of the shells:

,A ______Jl ---B ~

I I I I I I I I( FIGURE 1. Point of measurement of pleurotomarian shell: A, maximum diameter; B, minimum diameter; C, height; D, height of body whorl; E, depth of slit along upper margin; F, depth of slit along lower margin. 744 Bulletin of Marine Science [15(4) 1. Animals with a tuberculated surface; a triangular platform behind the operculum, divided lengthwise by a deep groove in the middle; shell large, diameter 70-190 mm 2. I. Animals with the triangular platform on the back without a longitudinal groove; shell smaller, 45-50 mm in diameter 3. 2. Shell with an open, deep umbilicus; slit long: Entemnotrochus Fischer 2. Shell without an umbilicus; slit short. External part of columella strongly thickened and curved like the letter S ...... Mikadotrochus Lindholm 3. Shell without an umbilicus; slit short. External part of columella not thickened and not curved Perotrochus (Fischer)

Some authors still prefer to treat these taxa as subgenera of Pleuro- tomaria s. lat., or to ignore them altogether. Abbott (in Wagner & Abbott, 1964: 13) expresses doubt about the generic validity of these groups and refers all Recent species to a broad Pleurotomaria with three subgenera, a view shared by Shikama & Horikoshi (1963: 5). With the discovery of more and more living pleurotomarian species, characters placing the generic groupings on a firmer basis emerge, and it seems preferable at this time to accept these taxa at the level recognized by Knight et al. (1960). Entemnotrochus is sharply distinguished by the widely open umbilicus, very deep slit, large size, and dwindling sculpture on the later whorls. Among the non-umbilicate forms, the thickened sigmoid columellar lip is not in itself a satisfactory character for the separation of Mikadotrochus from Perotrochus, as all the species have this character to a greater or lesser degree, but both of the species originally included in Mikadotrochus have an exceptionally shallow slit, which justifies retention of the genus. The remaining non-umbilicate species, comprising the genus Perotrochus, have in common the slit of moderate depth positioned below mid-whorl, and a weakly to moderately thickened, sigmoid columellar lip, but they range from rather small and solid to quite large and thin. In the smaller forms, such as quoyanus, the slit and fasciole are conspicuously below mid-whorl while in the larger ones, such as teramachii, they are but slightly below. In my opinion, the latter are at least subgenerically distinct from the small species of Perotrochus because of the size, shape, and light weight of the shell, as well as the higher position of slit and fasciole. The generic level taxa here recognized may be summarized as follows: Entemnotrochus Fischer (Ty P e - spede s, Pleurotomaria adansoniana Crosse & Fischer, 1861, by monotypy). Large, trochiform, widely umbilicate, as broad as or broader than high, columella not notably thickened and without strong sigmoid curvature; whorls weakly convex or obtusely angu- Jar, periphery of body whorl angular or subangular, base weakly convex or 1965] Bayer: Pleurotomariid Gastropods 745 almost flat; sinus and fasciole placed above midpoint between suture and periphery, slit deep, about one-half of circumference of last whorl; sculpture of low, broad spiral cords and fine axial threads, tending to become obscure on the later whorls of large specimens. (E. adansonianus, rumphii.) Perotrochus Fischer (Type-species, Pleurotomaria quoyana Fischer & Bernardi, 1856, by monotypy). Rather small to moderate in size, turbiniform to trochiform, base shallowly excavate but not perforate; columella weakly callused, lip moderately thickened and more or less sinuous; whorls flat-sided to moderately convex, periphery of body whorl rounded or subangular, base slightly to moderately convex; the sinus and its fasciole lie below the midpoint between suture and periphery, the slit shallow, only one-fourth the circumference of the last whorl; sculpture of spiral and axial riblets, cancellate, beaded at intersections. (Group A: Perotrochus quoyanus, amabilis, gemma n. sp., lucaya n. sp.; group B: P. africanus, midas, teramachii Kuroda, "teramachii" Habe non Kuroda; group C: P. hirasei.) Mikadotrochus Lindholm (Type-species, Pleurotomaria beyrichii Hilgen- dorf, by origin,!l designation). Moderately large, trochiform, base shallowly excavate but not perforate, from slightly broader than high to slightly higher than broad; columellar lip distinctly thickened by pearly callus and with a strong sigmoid curvature; whorls weakly convex, body whorl peripherally rounded or subangular, base moderately to slightly convex; sinus and fasciole somewhat below midpoint between suture and periphery, slit shallow, extending one-fifth or less of the circumference of the last whorl, upper margin advanced beyond the lower; sculpture of obscurely nodose or beaded spiral cords, axial riblets minute or obsolete (M. beyrichii, salmianus, schmalzi.) One of the three new species described in this paper (Perotrochus midas) undergoes such spectacular changes in shape during the growth of the shell that at certain points in development it could not be referred readily to any described genus of Pleurotomariidae, or perhaps even to the family. However, as only one specimen is known, the possibility of abnormality cannot be excluded, and the species is referred to Perotrochus. The following key expresses the salient differences between the species of pleurotomariids now recognized in the Western Atlantic Ocean:

1. Slit very deep, extending about 1/2 the circumference of the last whorl, situated above the midpoint between suture and periphery; shell large, trochoidal, widely and openly umbilicate. Entemnotrochus adansonianus 1. Slit shallow, extending only Y4 of the circumference of the last whorl, situated below the midpoint between suture and periphery; shell smaller, not openly umbilicate 2. 2. Shell large, over 100 mm in diameter, thin, with inflated whorls and deeply impressed sutures. Color yellow with pinkish orange 746 Bulletin ot Marine Science [15(4) suffusion and axial streaks on the later whorls, the outer surface with a metallic sheen. [Early post-nuclear whorls becoming almost planispiral after the third, resulting in a truncated spire, resuming a steeper slope after the fifth whorl.] Perotrochus midas, n. sp. 2. Shell smaller, less than 75 mm in diameter, usually under 50 mm, rather thick, with whorls only moderately inflated and sutures weakly impressed if at all 3. 3. Shell trochoidal, spire flat-sided, whorls not inflated, sutures not impressed 4. 3. Shell turbiniform, sutures moderately impressed and the later whorls somewhat inflated 5. 4. Sculpture very fine: on last (eighth) whorl, 18 beaded spiral cords above fasciole, 8 between fasciole and periphery; fasciole convex [normal?] on final whorl, with 7 cords. Color cream white with very faint axial streaks of pale yellowish brown Perotrochus Zucaya, n. sp. 4. Sculpture coarser, only 8 spiral cords above and 6 below fasciole on equivalent whorl; fasciole flush, with 2-4 cords. Conspicuous color pattern of irregular axial streaks of reddish or orange brown on a cream white yellowish ground color; spiral cords pale Perotrochus gemma, n. sp. 5. Shell moderately large (diameter reaching about 70 mm), spire with a concave slope (coeloconoid), apical angle 54°; columellar lip somewhat thickened and with strong sigmoid flexure. Color pattern conspicuous, rusty red axial streaks on a cream white ground color Perotrochus amabilis 5. Shell smaller (diameter reaching about 50 mm), spire with a straight or slightly convex slope, apical angle about 70°; columellar lip with a moderate sigmoid flexure. Color pattern inconspicuous, pale brownish Perotrochus quoyanus

DESCRIPTIONSOF NEW SPECIES Perotrochus midas, n. sp Figs. 2-8 MateriaZ.-One specimen from Northwest Providence Channel, 15 miles NW of Great Stirrup Cay, Berry Islands (25°56'N, 78°09'W, to 25°56'N, 78°05'W), 595-711 meters, R/V GERDA sta. G-679, 20 July 1965: HOLOTYPE,U.S. National Museum no. 655930. Description.- The shell is large, thin, broadly turbiniform, with bluntly rounded apex (Figs. 2, 3). Whorls 9% including the protoconch, which consists of one glassy, translucent, unsculptured whorl faintly delimited 1965] Bayer: Pleurotomariid Gastropods 747 from the following sculptured whorls of the teleoconch (Fig. 6). The early teleoconch is turbiniform, with rapidly expanding whorls and a spire angle of 97°, but after about 2 Y2 turns the whorls flare broadly and become practically planispiral (Figs. 7-9). The result is a shell suggestive of Eotomaria (d. Eotomaria canalifera Ulrich as illustrated by Knight et al., 1960: 205, fig. 118, 7) but even more depressed and with a differently placed slit and fasciole (Fig. 8, a). Subsequently, the coiling assumes a steeper angle so the shape of the shell becomes lenticular (Fig. 8, b) and resembles the Mesozoic Obornella (d. Obornella plicopunctata as illustrated by Knight et al., 1960: 216, fig. 131, la-lb). From about the fourth through the sixth whorls, the periphery is prominent and flattened, standing out as a squarish carina resembling the milled edge of a coin (Fig. 8, a). The shell becomes cyrtoconoid as it grows larger (Fig. 8, c), and at full size resembles the large, thin-shelled species of Perotrochus (e.g., africanus and teramachii), but with a blunt spire (Fig. 4). This condition is reminiscent of the Triassic Eymarella, in which the early whorls are discoidal, the later ones trochoid aI, producing a blunt apex (cf. Eymarella scalari- formis as shown by Knight et al., 1960: 216, fig. 130, 3). The last four whorls are inflated, with a moderately convex ramp, steeply sloping, almost vertical sides, and bluntly angular periphery; the angle of the spire is 90° here. The base is convex, narrowly excavate in the umbilical region but not perforate. The aperture is ovate, the outer lip with a moderately deep sinus extending about Y4 of the peripheral circumference. The slit and fasciole are located approximately midway between suture and periphery, but because of the convex base they lie rather high on the body whorl and form an obscure shoulder separating the more or less convex ramp from the steep, almost straight sides. The columellar margin of the aperture is only slightly thickened, the sigmoid twist is moderate, and the pearly callus over the umbilical region is of very limited extent. The sculpture consists of spiral cords and axial riblets which produce a beaded surface. Below the fasciole, the axial component is practically vertical, crossing the spirals at right angles to produce beads that are almost square, whereas above the fasciole the axial element is strongly prosocline so that the collabral riblets cross the spirals obliquely and produce beads that are elongated along the axis of the spirals. On the body whorl there are about 3'0 spiral cords above the fasciole and about 18 below. On the eighth whorl there are 15 spirals above and 9 below the fasciole. They increase in number by dichotomy so they tend to occur in pairs. On the base there are about 75 spiral cords intersected by collabral growth riblets, resulting in a weakly beaded surface. The fasciole is slightly concave and marked by three faint cords, of which the central one is strongest, and close-set raised lunules. Both upper and lower edges of the slit are flared outward so that the fasciole is bordered by raised keels after the slit closes. The fasciole 748 Bulletin of Murine Science [15(4)

FIGURE 2. PerotrochLis midas. n. sp. Holotype. Profile and apical views (x 0.76 approx.). 19651 Bayer: Pleurotomariid Gastropods 749

FIGURE 3. Perofrochus midas, n. sp. Holotype. Apertural and basal views (x 0.76 and 0.84 approx.). 750 Bulletin of Marine Science l15(4)

FIOURE 4. Perotrochus midas, n. sp. Holotype. AperturaI view (x 0.93 approx.). originates on the upper surface of the first post-nuclear whorl, moving to a lateral position as the space between suture and fasciole widens to form the ramp (Fig. 6). As the whorls become flattened, the fasciole comes to lie on the outer face of a broad, spiral elevation between the suture and the raised periphery. As the slope of the whorls increases, the fasciole moves to its definitive position at the shoulder. The ground color of the shell is golden yellow above, with the iridescence of the nacreous layer showing through the translucent porcellaneous layer. At about the fifth whorl, a darker yellow spiral band appears just below the suture, becoming broader and more distinct on the following whorl, then more diffuse. Its darker lower edge moves to the margin of the fasciole as the shell enlarges, forming an orange line. A similar orange marginal line appears along the lower edge of the fasciole at about the seventh whorl. Axial streaks of pinkish orange appear on the seventh and eighth whorls, progressively darkening as the shell increases in size. On the body whorl a pinkish general suffusion appears, giving the shell an exceptionally beautiful 1965] Bayer: Pleurotomariid Gastropods 751 pinkish-gold coloration. The base is pinkish cream with darker stfli:aks following the growth lines. The interior of the aperture is lined with iridescent nacre except on the parietal wall where the color of the base shows through a transparent glaze. A thin orange line follows the edge of the nacreous layer along the rim of the slit and around its closure. There are traces of an extremely thin, horny periostracum remaining on many parts of the outer surface. Measurements.-Height 88.8 mm; maximum diameter 118.3 mm, minimum diameter 102.2 mm; height of body whorl 68 mm; depth of slit 60 mm; width of fasciole on body whorl 5 mm, on penultimate whorl 3.7 mm. Remarks.-This shell suffered some breakage during growth, which might be the reason for the drastic changes in shape. However, every pleurotomarian specimen shows evidence of such damage, often more severe than any of the breaks in this specimen. In every other case, the injuries result only in a disruption of the ornamentation over part of the shell, not the massive changes in shape seen here. Although the truncated spire may

FIGURE 5. Perotrochus midas, n. sp. Holotype. Apical view (X 0.89 approx.). 752 Bulletin of Marine Science 1/5(4)

FIGURE 6. Perotrochus midas, n sp. Holotype. Oblique and vertical views of protoconch and first whorl of teleoconch (X 53). 1965] Bayer: Pleurotomariid Gastropods 753 indeed be a normal condition, the existence of only one specimen leaves the matter open to question for the moment. Decision regarding the generic status of P. midas is therefore postponed pending the discovery of addi- tional specimens. Perotrochus africanus (Tomlin) is similar to P. midas but the whorls are less inflated, the slit is lower on the whorls, the fasciole is not so distinctly keeled along both edges, and the axial sculpture is weaker so the surface is not so distinctly beaded. The columella is more strongly twisted, the nacreous callus is more extensively developed on the umbilical area, and the nacre of the parietal wall is exposed within the aperture. In all reported specimens of P. africanus the spire is conical and slopes uniformly throughout the growth of the shell.

FIGURE 7. Perotrochus midas, n. sp. Holotype. Profile view of apex (Scale represents 5 mm.)

Perotrochus teramachii Kuroda is a similar species from Japanese waters but has a more regularly conical, trochoid spire with whorls less inflated and the sutures not so deep. The sinus is not quite so high on the whorl as in P. midas, and the sculpture as shown by photographs is not so strongly developed. The color of P. teramachii is described as dark orange with red irregular stripes and white cloudy spots, and red spirals on the base. The pleurotomariid illustrated by Kira (1961) and Habe (1962) as P. teramachii is even more similar to P. midas in its low spire and the high location of its slit, but according to Habe's figure the color markings are predominantly red and yellowish on an almost white ground. The shell has not been described and only Shikama & Horikoshi (1963) have speculated as to its identity. A meaningful comparison with the present specimen therefore cannot be made as yet. From all these forms, the new species differs in its obtuse spire which reflects the ontogenetic changes in shape of the shell, from turbiniform to virtually planispiral back to turbiniform. Such change in shape during 754 Bulletin of Marine Science [15(4) 1965] Bayer: Pleurotomariid Gastropods 755

FIGURE 9. Perotrochus midas, n. sp. Holotype. Oblique view of apical whorls (X 5 approx.) and detail of sculpture (X 5 approx.). 756 Bulletin of Marine Science [15( 4) growth has not been reported in any other living pleurotomarian. Perotrochus lucaya, n. sp Figs. 10-12, 13A-B Material.-One specimen from Northwest Providence Channel, off Lucaya, Grand Bahama Island (26°29'N, 78°40'W), 366-275 meters, RjV GERDA

FIGURE 10. Perotrochus [ucaya, n. sp. Holotype (X 1.65 approx.). 1965] Bayer: Pleurotomariid Gastropods 757 sta. G-704, 22 July 1965: HOLOTYPE, U.S. National Museum no. 655931. Description.-Shell trochoidal (Fig. 10), rather small, consisting of eight whorls and thus probably not fully grown. Apical angle (first four whorls) 0 76°, mean angle of spire 79 • The protoconch forms the first smooth, glassy whorl weakly delimited from the teleoconch. Formation of the teleoconch takes place by the deposition of a succession of crescentic extensions from the outer lip; these are marginally thickened, forming arcuate growth riblets, between which the surface is sculptured by several diverging threads (Fig. 11). At first, the anal sinus is shallow and lies near the suture, consisting simply of a slight curvature in the edge of the outer lip. As more crescentic increments are added to the margin of the aperture, the sinus deepens and moves away from the suture. A series of fan-shaped growth-increments is inserted between sinus and suture, at first sloping down toward the suture, later away from it and forming a ramp. As growth proceeds, the bottom of the sinus is filled in by a succession of marginally thickened, lunate growth-increments curved in the direction opposite those of the growing margin on either side, thus beginning the formation of the fasciole with its crescentic lunules. Within the first revolution of the teleoconch, the sinus and fasciole have moved to a position on the outer face of the whorl about midway between suture and periphery, and the fasciole has become distinctly impressed. The successive marginal thickenings, which produce the collabral growth riblets, result also in the thickening of the edge of the slit, so that the margins of the fasciole are raised after the slit has closed. The later whorls of the teleoconch are not inflated, resulting in an almost perfectly flat-sided cone, with sutures scarcely impressed and very inconspicuous. The base is moderately convex, with a faintly indicated umbilical depression. The sculpture consists of fine spiral cords beaded at their intersections with weak axial growth riblets (Fig. 13, a-b). The slit is short, 20 mm along its upper margin, thus about 14 the circumference of the last whorl. On the body whorl, the fasciole is slightly convex, raised above the surface of the whorl, and sculptured by five beaded cords, three strong and two somewhat weaker; on the penultimate and earlier whorls it is flush with the surface and the number of spiral cords is less: near the end of the seventh whorl there are three, only one near the end of the sixth, and on the fifth and earlier whorls the fasciole is sculptured only by lunules and is slightly impressed. On the final whorl there are 17 beaded spiral cords above the fasciole, and 7 between fasciole and periphery. The columellar lip is only slightly thickened, as would be expected in a young shell, but it has a distinct though moderate sigmoid flexure as it emerges from the base (Fig. 10). The color of the shell is very pale tan with faint axial streaks of yellowish brown. The interior of the whorls is nacreous except on the parietal wall 758 Bulletin of Marine Science [15(4)

FIGURE 11. Perotrochus lucaya, n. sp. Holotype. Oblique and vertical views of protoconch and first whorl of teleoconch (X 53). 1965] Bayer: Pleurotomariid Gastropods 759 where only a narrow band of nacre is exposed adjacent to the suture. The remaining part of the base lying within the aperture is covered by a transparent glaze. There are traces of exceedingly thin, yellowish periostracum persisting in the fasciole and in the depressions of the sculpture. Measurements.-Height 28 mm; maximum diameter 32 mm, minimum diameter 30 mm; height of body whorl 20.5 mm; depth of slit 20 mm, width of fasciole 1.4 mm.

FIGURE 12. Perotrochus lucaya, n. sp. Holotype. Profile view of apex. (Scale represents 5 mm.)

Remarks.- The small size and pale coloration of P. lucaya suggest relationship with P. quoyanus. However, it differs in the flat-sided spire with the sutures scarcely impressed, and in the finer sculpture. On the final (eighth) whorl, there are 17 spiral cords above the fasciole and 7 below, as compared with 6-8 above and 4-5 below on the eighth whorl of P. quoyanus. This is outside the range of variation in the small suite of P. quoyanus in the collections of the U.S. National Museum. The sculptural differences separating lucaya from quoyanus are of an order of magnitude similar to those separating Mikadotrochus beyrichii and M. salmianus (compare Figs. 31 and 32), which are clearly recognized as distinct species.

Perotrochus gemma, n. sp Figs. 13C, 14-16, 22D Material.-One specimen (dead shell) from Barbados, 100 fathoms, A. R. Cahn, 1965: HOLOTYPE,Academy of Natural Sciences, Philadelphia, no. 302134. One specimen (collected alive or very recently dead) from Barbados, off west coast between St. James and Speighstown, 100 fathoms, John Finlay, February 16, 1961: PARATYPE,in Mr. Finlay's private cabinet. 760 Bulletin of Marine Science [15(4)

FIGURE 13. Comparison of sculpture. A, Perotrochus lucaya, 8th whorl; B, P. lucaya, 6th and 7th whorls; C, P. gemma, holotype 8th whorl; D, P. quoyanus, USNM 639048, 8th whorl (all X 5,2,) 1965] Bayer: Pleurotomariid Gastropods 761

FIGURE14. Perotrochus gemma, n. sp. Top, paratype, private collection of Mr. John Finlay. - Bottom, halotype, Academy of Natural Sciences, Phil- adelphia (x 1.2 approx.).

Description.-Shell of moderate size, trochoid, similar to P. quoyanus but more regularly conical, with less inflated whorls, weakly impressed sutures, 0 and flatter base. Apical angle (first five whorls) 57 , mean angle of spire 640 -750. Protoconch smooth, about one whorl; slit and fasciole originating near the suture as in P. lucaya and P. midas, in the subsequent revolution moving to a position slightly above mid-whorl. In the following turns, the fasciole gradually moves toward its ultimate position and by the eighth whorl lies below midpoint. The sculpture consists of the usual spiral and axial elements with the former dominating, raised into low, rounded tubercles where intersected by the latter (Figs. 13C, 22D). On the body 762 Bulletin of Marine Science [15(4)

FIGURE 15. Perotrochus gemma, n. sp. Top, paratype. - Bottom, holotype (X 1.2 approx.). whorl there are 9-10 spiral cords above the slit and 6 below, with 2-4 on the fasciole. The slit is short as in P. quoyanus, about 1;4 of the circumference of the last whorl. The fasciole is flush with the surface and follows the contour of the shell on the later whorls, impressed and slightly concave on the early whorls. The periphery is bluntly angular, the base almost flat and sculptured with about 30 obscure to moderately strong spiral cords cancellated by collabral growth lines more or less distinctly raised at ]965] Bayer: Pleurotomariid Gastropods 763 intervals to form radial riblets. The aperture is roughly quadrate, the columellar lip somewhat thickened and sigmoidally bent. The umbilical area is shallowly excavate, with only a small area immediately surrounding the columella covered with pearly callus. The ground color is whitish to yellowish cream heavily marked with broad axial streaks of orange brown or reddish brown. For the most part the spiral cords are not marked by the dark axial streaks, which thus are crossed by pale lines of ground color. The base is pale, almost white, faintly suffused with yellowish or pinkish and weakly rayed with reddish brown collabral streaks darkest near the periphery. Measurements.-(Holotype) Height 42 mm; maximum diameter 46.5 mm, minimum diameter 43.5 mm; height of body whorl, 23 mm; depth of slit along upper margin 32 mm, along lower margin 21 mm; width of slit about 2.5 mm, but edges mostly broken to a width of about 3 mm.-(Paratype) Height 38 mm; maximum diameter 44.8 mm, minimum diameter 42.5 mm; height of body whorl 22 mm; depth of slit along upper margin 29 mm, along lower margin 20 mm; width of slit 2 mm. Remarks.- This species is similar to P. lucaya in shape but is more coarsely sculptured and more brightly colored. It differs from P. quoyanus in its almost flat-sided whorls, slightly impressed sutures, and conical spire, as well as its bright coloration. On first glance, P. gemma resembles a diminutive P. hirasei, especially in color.

FIGURE ]6. Perotrochus gemma, n. sp. Holotype. Profile view of apex (Scale represents 5 mm.) 764 Bulletin of Marine Science [15(4) 1965] Bayer: Pleurotomariid Gastropods 765

PREVIOUSLY KNOWN WESTERN ATLANTIC SPECIES Perotrochus quoyanus (Fischer & Bernardi) Figs. 13D, 17-21, 22A-B Pleurotomaria Quoyana Fischer & Bernardi, 1856: 165, pI. 5, figs. 1-3. (Marie Galante, Antilles.) . Pleurotomaria Quoyana, Crosse & Fischer, 1861: 155 et seq. [Comparative remarks.] Pleurotomaria Quoyana, Crosse, 1882:14. Pleurolomaria Quoyana, Sowerby in Reeve, 1874: species 2, pI. 1, fig. 2. Pleurotomaria Quoyana, Dall, 1881 :78. (Barbados, in 73 and 84 fms.) [Second and third known specimens.] Pleurotomaria Quoyana, Dall in Agassiz, 1888 :69, fig. 289. Pleurotomaria (Perotrochus) Quoyana, Dall, 1889:397, pI. 29, fig. 1; pI. 31, fig. 1; pI. 37, fig. 5. (Barbados: Blake sta. 290, 73 fms; sta. 296, 84 fms, Yucatan, near Arrowsmith Bank, Albatross sta. 2354, 130 fms.)

FIGURE 18. Perotrochus quoyanus (Fischer & Bernardi). Top, specimen from Barbados, USNM 95097. - Bottom, specimen from Anegada, USNM 639048 (X 1 approx.). 766 Bulletin of Marine Science [15(4) Pleurotomaria Quoyana, DaH, I889a:168, pI. 29, fig. 1; pI. 31, fig. 1; pI. 37, fig. 5. [No descriptive text; figures identical with preceding.] Pleurotomaria (Perotrochus) quoyana, Pilsbry, 1890: 70, pI. 56, figs. 4-6 [Figures and description after Fischer & Bernardi.] Pleurotomaria Quoyana, Bouvier & Fischer, 1899: 194 et. seq., passim; 206, pIs. 1-4. [Historical resume; description of anatomy.] Pleurotomaria Quoyana, Schmalz, 1901:35, pis. 8, II, 12. Pleurotomaria quoyana, Henderson in Nutting, 1919:90, pI. 21, fig. 8. (Off Spring Gardens, Barbados, 100 fathoms.) [Dead shell, now in U.S.N.M.] Pleurotomaria quoyana, Wagner & Abbott, 1964:14. (Gulf of Mexico- West Indies.)

FIGURE 19. Perotrochus quoyanus (Fischer & Bernardi). Top, specimen from Barbados, USNM 95097. - Bottom, specimen from Anegada, USNM 639048 (X 1 approx.). 1965] Bayer: Pleurotomariid Gastropods 767 Material.-Not yet collected in the Straits of Florida by R/V GERDA. HOLOTYPE:Height 35.2 mm; maximum diameter 45.1 mm, minimum diameter 41 mm. From Marie Galante, near Guadeloupe, Lesser Antilles. British Museum (N.H.), register no. 1948.5.12.2. Figure 17. The collections of the U.S. National Museum contain the following: 1. Collected alive: height ca. 43 mm; maximum diameter ca. 50 mm (lip broken), minimum diameter 46 mm; depth of slit measured along upper edge 30 mm: Barbados, 13°11'54"N, 59°38'45"W, 73 fathoms, BLAKEsta. 290, March 9, 1879. USNM 95097. (Fig. 18.) 2. Dead shell: height 41 mm; maximum diameter 48 mm, minimum diameter 46 mm; depth of slit measured along upper edge ca. 35 mm: Yucatan, off Arrowsmith Bank, 20059'30''N, 86°23'OO"W, 130 fathoms, ALBATROSSsta. 2354, Jan. 22, 1885. USNM 95098. 3. Dead shell: height 40 mm; maximum diameter 47 mm, minimum diameter 44 mm: Barbados, off Pelican Island, 100 fathoms. State Uni- versity of Iowa Barbados-Antigua Expedition, sta. 6. USNM 501185. 4. Collected alive: height 46 mm; maximum diameter 57 mm, minimum diameter 51 mm; depth of slit measured along lower edge

FIGURE20. Perotrochus quoyanus (Fischer & Bernardi)? Specimen from Bermuda, MCZ 229643 (X 1.8 approx.). 768 Bulletin of Marine Science [15(4) 3'0 mm: northwest of Anegada Island, West Indies, 14'0 fathoms. Johnson- Smithsonian Deep-Sea Expedition, sta. 102. USNM 639'048. (Fig. 18.) The collections of the Museum of Comparative Zoology, Harvard University, contain the following (Turner 1961): 1. Collected alive: Sandy Bay, Barbados, 75-10'0 fathoms, HASSLER Exped., stas. 217-22'0, December 29, 1871. 2. Collected alive: Barbados, off Bridgetown, 13°'05'24"N, 59°38'45" W, 84 [85] fathoms, bottom temp. 61.5°F, BLAKEsta. 296, March 1'0, 1879.

FIGURE21. Perotrochus quoyanus (Fischer & Bernardi), USNM 639048. Profile view of apex. (Scale represents 5 mm.)

3. Dead shell: Cuba, off Bahia Corrientes, 21 ° 47' 3'0" N, 84° 32' 03" W, 615 fathoms, ATLANTISsta. 2953. 4. Collected alive, soft parts preserved: height 24 mm; maximum diameter 27.5 mm, minimum diameter 25 mm. Bermuda, 5 mi. east of St. Davids Island, 30'0 fathoms. S.K. Roberts. MCZ 229643. (Fig. 2'0.) This shell is difficult to reconcile with P. quoyanus. It is trochoidal, with a coeloconoid spire and rather angular periphery, perhaps because of its small size. The base is moderately convex. The upper margin of the outer lip does not project so far beyond the lower as in larger specimens of quoyanus, a feature possibly associated with small size, but also reminiscent of P. amabilis. The shell consists of 9 whorls, of which the protoconch is lost. The last whorl shows a slight tendency toward inflation above the slit, a feature that becomes conspicuous in larger specimens of both quoyanus and amabilis. The spiral sculpture is not elevated into cords 1965] Bayer: Pleurotomariid Gastropods 769

FIGURE 22. Comparison of sculpture. A, Perotrochus quoyanus, USNM 95097, last whorl; B, P. quoyanus. USNM 639048, last whorl; C. P. amabilis, holotype USNM 635625, last whGrl; D, P. gemma, holotype ANSP 302134, last whorl (X 5.2). 770 Bulletin of Marine Science [15(4) but is composed only of raised beads on the collabral riblets. The color is cream white with axial streaks of yellowish tan, appearing somewhat brighter than in other specimens of quoyanus, but not so red as in amabilis. Direct comparison of this specimen with type material of P. amabilis may show that it is actually a young individual of that species. Remarks.-Although Perotrochus quoyanus was the first Recent pleurotomarian known to science, it is by no means the best-known species. Drawings of the type were published with the original description, and illustrations of a specimen collected by the U.S. Coast Survey steamer BLAKEwere published later by Dall (1888, 1889, 1889a). The assumption that there is but one species of small Perotrochus in the Western Atlantic has led to the indiscriminate identification of all specimens as P. quoyanus. The small specimen taken by RjV GERDAoff Lucaya, Grand Bahama, clearly could not be included in that species and thus pointed out the need for a more critical evaluation of all so-called quoyana material. Although much is still to be learned about the small Perotrochus, it is obvious that at least three species are included in the complex. However, there is a need for more abundant material to permit an investfgation of variation before the question of species discrimination in this group can be settled. As an aid in this direction, I present herewith the excellent photographs of the holotype of P. quoyanus shown in Figure 17, generously made available by the Trustees of the British Museum (N.H.) through the kindness of Mr. Peter Dance. All of the specimens that can be identified as P. quoyanus have in common the rather low, trochoid shape seen in the type, with moderately inflated whorls showing a distinct break in slope at the sutures which produces a spire that is almost gradate. The periphery of the early whorls is prominent and beaded (Fig. 21), but from Cl bout the sixth or seventh whorl it is rounded. In cross section, the outer wall of the whorls is moderately rounded (almost shouldered) above the fasciole, nearly straight (but sloping at an angle of about 25° from the vertical) below, with a rounded periphery and weakly to moderately convex base. The apical angle (first 4 post-nuclear whorls) is about 65-70° and the mean angle

of the spire 70-78 0. Although the color of the type was described originally as "rose pale, ornee de taches obscures, brunatres, surtout vers Ie dernier tour," it is now almost white with only the faintest suggestion of yellowish tan axial streaks (as shown by a color transparency provided by Dr. R. Tucker Abbott of the Academy of Natural Sciences of Philadelphia). Perhaps its present pale coloration is the result of fading, but all of the examples in the U.S. National Museum, including the one from BLAKE sta. 290 described by Dall (1881, 1889), are similarly pale, with faint yel10wish tan streaks. 1965] Bayer: Pleurotomariid Gastropods 771 The sculpture of all the specimens is similar in character but varies somewhat in prominence, from rather weaker than in the type, to stronger and more conspicuously beaded. The number of spiral cords on the body

rnJUKJ::. L.J. 1-~'VlfULflU') U"tUUH~':J ~DdY'l;:lJ' raJ.UlYP'l;", U1;;al"'lVHUlUIc; \JU'l;;U Museum, Rollins College, Winter Park, Florida (X 1.5 approx.). 772 Bulletin of Marine Science [15(4) whorl above the slit is 12-14, and the photographs of the type specimen indicate that it has about 16. Perotrochus amabilis (Bayer) Figs. 22C, 23 Mikadotrochus amabilis Bayer, 1963:489, fig. 1. (Southeast of Sombrero Light, Florida Keys, 120 fathoms.) Mikadotrochus amabilis, Fretter, 1964:172, figs. 1-6. [Anatomy of the type specimen.] Pleurotomaria amabilis, Wagner & Abbott, 1964:14. [Listed only.] Pleurotomaria (Mikadotrochus) amabilis, Shikama, 1964: 133, fig. 214. [Pho- tograph of second specimen dredged by J. Moore in the Gulf of Mexico.l Material Collected by R/V Gerda.-One specimen collected alive: southeast of Sombrero Light, Florida, between 24° 29' N, 80° 53' W, and 24° 30' N, 80° 50' W, 120 fathoms, sta. G-135, June 21, 1963. HOLO- TYPE, U.S. National Museum, no. 635625. Other Material.-One young specimen: Gulf of Mexico, off southern Florida, colI. Jim Moore. Paratype, Raines collection no. 1717, now in the Beal-Maltbie Shell Museum, Winter Park, Florida. (Another specimen collected at the same time is now in the Academy of Natural Sciences, Philadelphia.) Remarks.-Particulars regarding this species may be found in the original description cited above. Two of the four known specimens have been illustrated, the type (Bayer, 1963) and the larger of the two specimens dredged off the west coast of southern Florida by Mr. J. Moore (Shikama, 1964). The smaller of those two, a young specimen in perfect condition, is now illustrated in Figure 23. It is 35 mm high, maximum diameter 44 mm, minimum diameter 39 mm; depth of slit 29 mm. Entemnotrochus adansonianus (Crosse & Fischer) Fig. 24 Pleurotomaria Adansoniana Crosse & Fischer, 1861:163, pI. 5, figs. 1-2 (Habitat?) Pleurotomaria Adansoniana, Sowerby in Reeve, 1874: species 1, plate 1, figs. 1a, 1b. Pleurotomaria Adansoniana, DaH, 1881:78. (Barbados, in 69, 94, 200 fms.; BLAKE.) Pleurotomaria Adansoniana, Crosse, 1882:12, pI. 1, figs. 1-2. (Guadeloupe, 150 fms.) Pleurotomaria Adansoniana, Dall in Agassiz, 1888:69, fig. 288. (West Indies, Blake Exped.) [Refers to the specimens reported by DaH, 1881.] Pleurotomaria (Entemnotrochus) Adansoniana. DaH, 1889:400, pI. 30; pI. 31, figs 3-6; pI. 32, fig. 10; pI. 37, fig. 4 (Barbados: BLAKEsta. 276, 94 fms; sta. 278, 69 fms; sta. 291, 200 fms.) Pleurotomaria Adansoniana. DaH, 1889a:168, pI. 30; pI. 31, figs. 3-6; pI. 32, fig. 10; pI. 37, fig. 4. [No descriptive text; figures identical with those in DaH, 1889.] 1965] Bayer: Pleurotomariid Gastropods 773

FIGURE 24. Entemnotrochus adansonianus (Crosse & Fischer). A, spec~men from Northwest Providence Channel, GERDA sta. G-697. - B-E, specimen from Barbados, Blake sta. 276; photographs courtesy of the Smithsonian In- stitution. (x 0.5 approx.) 774 Bulletin of Marine Science [15(4) Pieurotomaria (Entemnotrochus) adansoniana, Pilsbry, 1890:72, pI. 56, figs. ]-3. [Figures and description from Crosse & Fischer.] Pleurotomaria Adansoniana, Bouvier & Fischer, 1899: 198 et seq., passim. [Historical resume of specimens; comparison of anatomy with that of quoyana.] Pleurotomaria Adansoniana, Schmalz, 1901 :33, pI. 3, fig. 2; pis. 4-5; pI. 8, fig. 4; pis. 9-10. Perotrochus adansonianus. Abbott, ]954:92, pI. 3, fig. d. lColor photograph of the specimen from BLAKEsta. 276, reported and figured by Dall, 188], 1888, 1889.] Entemnotrochus adansoniana, Turner, 1961: 162. (Bermuda, 110 fms. [new record]; Barbados, 69 and 94 fms. [BLAKEexped.]) Pleurotomaria (Entemnotrochus) adansoniana, Shikama & Horikoshi, 1963: 3, fig. 2. Pleurotomaria adansoniana, Wagner & Abbott, 1964: 13. (Caribbean to Brazil.) Material Collected by R/V Gerda.-Two fragments, the peripheral parts of half of the final whorl from two rather large individuals: Northwest Providence Channel, south of Grand Bahama Island, 26° 28' N, 78° 40' W, 278-329 meters; R/V GERDA, cruise 6511, haul G-526, March 3, 1965; 10-foot otter trawl. One large, complete but dead shell: Northwest Providence Channel, south of Grand Bahama Island, 26° 29' N, 78° 39' W, 247-374 meters; R/V GERDA, cruise 6528, haul G-697, July 22, 1965; 10-foot otter trawl. (Fig. 24A.) One fragment, the base of the final whorl of a large individual: North- west Providence Channel, south of Grand Bahama Island, 26° 27' N, 78° 43' W, 522-482 meters; R/V GERDA, cruise 6528, haul G-706, July 22, 1965; 10-foot otter trawl. Other material.-The collections of the U.S. National Museum contain: 1. Collected alive: Barbados, off Bridgetown, 13° 03' 50" N, 59° 37' OS" W, 94 fms., BLAKE sta. 276, March 5, 1879. (Fig. 24.) The Museum of Comparative Zoology at Harvard University has the following: 1. Collective alive: Barbados, off Bridgetown, BLAKE sta. 276. MCZ 119058. 2. Dead shell: Barbados, same station. MCZ 16824. 3. Dead shell: Barbados, off Bridgetown, 13° 04' 50" N, 59° 37' 40" W, 69 fathoms, BLAKE sta. 278, March 6, 1879. Remarks.-This species is very well characterized and requires no further description. The material collected by R/V GERDA, all more or less fragmentary, represents rather large individuals and suggests that there is a substantial population of the animals nearby, from which the shell fragments originated, As the bottom is very rough and steeply sloping in this area, it is quite 1965] Bayer: Pleurotomariid Gastropods 775 likely that the animals are living in water somewhat shallower than where the dead shell and fragments were taken. Specimens dredged in depths of 125 and 169 meters off Barbados by the BLAKE strengthen this supposition. However, due to the character of the bottom, it seems likely that, even though there is probably a good population of E. adansonianus living in moderate depths, it will be difficult to obtain many specimens for study and impossible to learn very much of their habits and ecology with the crude exploratory methods now in use. The complete, dead shell from haul G-687 (Fig. 24) is somewhat larger than the largest example in the Museum of Comparative Zoology as reported by Turner (1961). Measurements are: height 139 mm; maximum diameter 146.4 mm; minimum diameter 132.4 mm. Colors agree substantially with the color figure of the specimen in the U.S. National Museum given by Abbott (1954). RESUME OF OTHER RECENT SPECIES Entemnotrochus rumphii (Schepman) Figs. 25, 26 Pleurotomaria Rumphii Schepman, 1879: 163. (Moluccas.) Pleurotomaria Rumphii, Schepman, 1882:20, pI. 2, figs. 1-3. Pleurotomaria Rumphii, Crosse, 1882: 8. Pleurotomaria Rumphii, Sower by, 1884: 185, pI. 490, figs. 1-2. Pleurotomaria rumphii, Pilsbry, 1890:71, pI. 57, figs. 13-14. Pleurotomaria Rumphii, Schmalz, 1901: 32, pIs. 1-2; pI. 3, fig. 1. Entemnotrochus rumphii, Kuroda, 1936:250, text-figs. p. 253, fig. on title page of volume. (Tosa, Japan.) Entemnotrochus rumphii, Kuroda, 1955 :212, 216, pI. 9. (From an adjacent sea of Formosa.) Entemnotrochus rumphii, Kira, 1961 :5, fig. 5. [Reproduction of photograph published by Kuroda, 1955.J Pleurotomaria (Entemnotrochus) rumphii, Shikama & Horikoshi, 1963:3, fig. 3. [Reproduction of photograph published by Kuroda, 1955.J Pleurotomaria rumphii, Wagner & Abbott, 1964: 14. [Listed only.] Holotype.-Moluccas. Natuurhistorisch Museum, Rotterdam. (Fig. 25.) Remarks.-Only three specimens of this magnificent species appear to have been reported: the holotype from the Moluccas; a small example 71 mm in maximum diameter, from Tosa, Japan (Kuroda, 1936); and a large specimen, estimated at about 190 mm in diameter, from the vicinity of Formosa (Kuroda, 1955). Regrettably, the last two shells were victims of the ravages of World War II and they are now known only by photographs. Through the kindness of Professor T. Kuroda, I am able to reproduce here his photographs of the smaller shell (Fig. 26) to show the aspect of an immature specimen in comparison with a fully grown individual. 776 Bulletin of Marine Science [15(4) 1965] Bayer: Pleurotomariid Gastropods 777 778 Bulletin of Marine Science [15(4)

FIGURE 27. Perotrochus africanus (Tomlin). Off Durban, South Africa. Photographs courtesy of the Smithsonian Institution. 1965] Bayer: Pleurotomariid Gastropods 779 Perotrochus africanus (Tomlin) Fig. 27 Pleurotomaria afrieana Tomlin, 1948:2, pI. 1. (Off Durban, South Africa, on the crawfish grounds in 200 fathoms.) "Pleurotomaria" afrieana, Kuroda, 1955 :214. [Compared with Perolroehus teramaehii. Although the specific name is not formally combined with Perolroehus, the use of the spelling "africanus" in the comparative table indicates the author's intent.] Pleurotomaria (Perotroehus) africana, Shikama & Horikoshi, 1963:4, 5, text-fig. 4, pI. 1, fig. 2. [Superb color plate.] The collection of U.S. National Museum contains a specimen from off Durban, South Africa, which is illustrated in Figure 27. The shell is rather thin and light in weight, and the color is dull yellowish red with whitish streaks and blotches, as described for the type. Although the margins of the fasciole are somewhat raised and sharp, the resulting keels are equally inconspicuous and the upper one is not stronger than the lower as described in the type. The raised red marginal line bordering the slit as mentioned by Tomlin is not conspicuous, but within the aperture there· is a reddish line along the edge of the nacreous layer where it ap- proaches the margin of the slit. This feature is seen also in Mikadotrochus salmiana and Perotrochus midas. Shikama & Horikoshi (1963) suggest that the shell illustrated by Kira (1961) and Habe (1962) as P. teramachii may instead be P. africanus or a subspecies of it. It seems more likely, however, that it is a related but distinct species. Distribution.-South Africa, about 200 fathoms.

Perotrochus teramachii Kuroda Fig. 28 Perotroehus teramaehii Kuroda, 1955: 213, pI. 8. (Tosa, Japan.) Not Perotrochus teramachii, Kira, J 96 I :4, text-fig. [The figured shell differs from the type as illustrated by Kuroda.] Not Perotrochus teramaehii, Habe, 1962:], pI. 1, fig. 1. [Color figure, apparently the same specimen illustrated by Kira, 196].] Pleurotomaria teramachii, Shikama & Horikoshi, 1963 :4, 5, pI. 1. Pleurotomaria (Perotrochus) teramachii, Shikama & Horikoshi, 1963 :4, 5, pI. 1, fig. 1. [Superb color plate.] No specimens of this species have been available to me for examination. It seems to be known only from the holotype. The specimen illustrated as teramachii by Kira (1961) and Habe (1962) is obviously different. Shikama & Horikoshi (1963: 5) believe that it may be only subspecifically distinct from africanus, if not identical. The accompanying photographs of the type were kindly provided by Dr. T. Kuroda. 780 Bulletin of Marine Science [15(4)

..c 0.0 ::l o•... ..c•... 1965] Bayer: Pleurotomariid Gastropods 781 Perotrochus sp. indet. Fig. 29 Perotrochus teramachii, Kira, 1961 :4, text-fig. (Near Okinoshima, Kochi-ken; 400 m.) Not Kuroda, 1955. Perotrochus teramachii, Habe, 1962; 1, pI. 1, Fig. 1. Not Kuroda, 1955. This shell is different in shape and, apparently in color, from the type of teramachii. Shikama & Horikoshi (1963: 5) suggest a relationship with P. africanus. Although I have not been able to compare the actual specimens, the published photographs of the Japanese specimen show a more depressed shell with little sigmoid flexure of the columella and the slit rather high on the whorl, quite different from the specimen of P. african us in the U.S. National Museum (Fig. 27).

FIGURE29. Perotrochus sp. Okinoshima, Kochi-ken, Japan. Illustration adapted from Kim (1961) and Habe (1962). (X 1 approx.)

Perotrochus hirasei (Pilsbry) Fig. 30 Pleurotomaria hirasei Pilsbry, 1903: 36. Pleurotomaria (Mikadotrochus) hirasei, S. Hirase, 1934 [1938] :32, 125, pI. 59, fig. 1. [Good color figure.] Pleurotomaria hirasei, Taki, 1951: pI. 59, fig. 1. (Wakayama-ken.) [Identical figure.] Perotrochus (Mikadotrochus) hirasei, Kira, 1954:3, pI. 1, fig. 2. [Good color figure.] Perotrochus (Mikadotrochus) hirasei, Taki in Okada, 1960: 189, pI. 86, fig. 6. [Color figure.] Perotrochus (Mikadotrochus) hirasei, Kira, 1961 :3, pI. 1, fig. 2. [Color figure repeated from 1954 above.] 782 Bulletin of Marine Science [/5(4) ? Mikadotrochus salmiana, Shikama, 1961 :pl. 28, figs. 1-2; pI. 29, fig. 2. Not Rolle, 1899. Mikadotrochus hirasei, Kira, 1962:2, pI. 2, fig. 2. [Color figure from 1954 and 1961 reprinted in larger size.-j Pleurotomaria (Mikadotrochus) hirasei, Shikama & Horikoshi, 1953 :4, pI. 2, figs. 4-5. [Good color figures.] Pleurotomaria hirasei, Wagner & Abbott, 1964: 14. [Listed only.] This is probably the commonest J apanefe species and one of the most often illustrated pleurotomarians. The references cited in the fore- going synonymy are by no means all. Even though P. hirasei reportedly inhabits a somewhat deeper bathy- metric range (70-100 fms.) than does M. beyrichii (20-30 fms.), it is often collected in commercial fishing operations and hundreds of specimens therefore have found their way into museums and private collections.

FIGURE 30. Perotrochus hirasei (Pilsbry). Kii Peninsula, Wakayama-ken, Japan (X 0.6 approx.). 1965] Bayer: Pleurotomariid Gastropods 783 Thus, it is probably the only species of which enough specimens exist to permit a serious analysis of variation. Although P. hirasei is a large, heavy-shelled form, it has a deeper slit than do beyrichii and salmiana, thus is excluded from Mikadotrochus. It is here retained in Perotrochus, but differs from the other large-shelled species of that genus (atricanus, amabilis, midas, teramachii) by its thick, heavy shell. The U.S. National Museum contains four specimens from various Japanese localities. The figured example, in the collection of Dr. H. B. Owre, is about 85 mm high (apex incomplete), maximum diameter 91 mm, minimum diameter 87 mm. It comes from Kii Peninsula, Wakayama-ken, Japan. Mikadotrochus beyrichii (Hilgendorf) Fig. 31

Pleurotomaria Beyrichii Hilgendorf, 1877: 72. Pleurotomaria Beyrichi, von Martens, 1880:33, pI. 7. [Color figures of holotype.] Pleurotomaria Beyrichi, Crosse, 1882: 16. Pleurotomaria (Perotrochus) beyrichi, Pilsbry, 1890:71, pI. 56, figs. 7-9. Pleurotomaria Beyrichi, Dautzenberg & Fischer, 1898:218, pI. 11. [Resume of all known specimens; quotation of original description; description of a new specimen from Japan, with illustrations of shell and apical whorls.] Pleurotomaria Beyrichii, Bouvier & Fischer, 1899:201-203. [Historical resume.] Pleurotomaria Beyrichi, Schmalz, 1901:34, pIs. 7, 13. Perotrochus (Mikadotrochus) beyrichii, Kira, 1954 and 1961 :3, pI. 1, fig. 1. [Excellent color figure.] Mikadotrochus beyrichii, Kira, 1962:2, pI. 2, fig. 1. (Kanto District, Japan, 20-100 fms.) [Color plate identical with that of 1961 but printed slightly larger than natural size.] Pleurotomaria (M ikadotrochus) bey rich ii, Shikama & Horikoshi, 1963: 4, pI. 2, fig. 1. (Sagami Bay, Japan.) [Excellent color figure.] Pleurotomaria (Mikadotrochus) beyrichii, Lindholm, 1927:409-414, passim. Mikadotrochus beyrichii, Shikama, 1961:500-506, passim; pI. 28, fig. 6; pl. 29, fig. 3. Pleurotomaria beyrichii, Wagner & Abbott, 1964: 14. [Listed only.] The upper specimen shown in Figure 31 is in the collection of the U.S. National Museum. It is 62 mm high and has a maximum diameter of 64 mm. There are 6 spiral cords above the fasciole and 4 below on the body whorl, and 19 cords on the base. The color pattern of the base is radial, and the fasciole lacks marginal color lines. The specimen shown at the bottom of Figure 31 is the one described and figured by Dautzenberg & Fischer (1898), deposited in the lnstitut Royal des Sciences Naturelles de Belgique. It is 65 mm in height, with a maximum diameter of 71 mm. The photographs are copied from color transparencies kindly made available by Dr. R. Tucker Abbott. 784 Bulletin of Marine Science [15(4)

FIGURE 31. Mikadotrochus beyrichii (Hilgendorf). Top, specimen in the U. S. National Museum; photographs courtesy of the Smithsonian Institution (X 0.8 approx.). - Bottom, hypotype (Dautzenberg & Fischer, 1898) in Institut Royal des Sciences Naturelles, Brussels; photographs courtesy of Dr. R. T. Abbott (X 0.7 approx.). 1965] Bayer: Pleurotomariid Gastropods 785 Of all known pleurotomarians this species inhabits the shallowest water, occurring commonly in 20-30 fathoms, but as deep as 100.

Mikadotrochus salmianus (Rolle) Figs. 32, 33

Pleurotomaria salmiana Rolle, 1899:62. (In scopulo Okinose Japoniae prof. 300 metr.) Pleurotomaria salmiana, Rolle, 1899a: 161, plate. (Japan, Okinose Riff, cca. 150 Faden Tiefe, 12 Mai 1896.) Pleurotomaria Salmiana, Schmalz, 1901: 34, pI. 6. Pleurotomaria Hirasei, Y. Hirase, 1907: pI. 1. Not Pilsbry, 1903. [Included in original synonymy of schmahi.] Pleurotomaria (Mikadotrochus) salmiana? S. Hirase, 1934:32, 125, pI. 59. fig. 2. [Included in original synonymy of schmalzi.] Perotrochus (Mikadotrochus) salmiana. Kira, 1961 :4, fig. 3. Mikadotrochus salmiana, Habe, 1961: I, pI. 1, fig. 2. [In original synonymy of schmahi.] Mikadotrochus schma/Zi Shikama, 1961 :505, pis. 28-29. (Southwest Tosa and off Mishima, Iwami (?).) Not Mikadotrochus salmiana, Shikama, 1961:pI. 28, figs. 1-2; pI. 29, fig. 2. [=Perotrochus hirasei Pilsbry?] Mikadotrochus schmahi, Habe, 1962: I, pI. 1, fig. 2. Pleurotomaria (Mikadotrochus) schma/Zi, Shikama & Horikoshi, 1963 :4, pI. 2, fig. 3. (Kashiwajima, Tosa, Kochi Pref., Japan.) Not Pleurotomaria (Mikadotrochus) salmiana, Shikama & Horikoshi, 1963 :4, pI. 2, fig. 2. [Probably = hirasei.] The specimen shown in Figure 32, from Kashiwajima, Tosa, Japan, in the collections of the U.S. National Museum, agrees very closely with the original description of Pleurotomaria salmiana but is somewhat smaller than the type specimen. It is 83 mm high and has a maximum diameter of 8] mm; the slit is about 35 mm deep along its upper margin, 16 mm along the lower. On the body whorl there are 17 spiral cords (of which 5 are weak intercalary cords not yet strongly developed) above the fasciole, 5 between fasciole and periphery, and 29 on the base. The reddish orange markings are distinct all the way to the apex of the shell, the base has faint radial rays of brownish orange, inside the aperture the slit has a thin orange marginal line, the fasciole is edged with an orange line on both sides and is sculptured with two cords. It is evident from the original description (Shikama, ] 961), published figures (Rabe, 1962; Shikama & Rorikoshi, 1963), and photographs of a specimen in the collections of Kyoto University kindly supplied by Dr. T. Kuroda, that Mikadotrochus schmalzi agrees in all respects with the original description of P. salmiana Rolle. Shikama (1961: 506) diag- noses his species as follows: "Bandlike colouration of whorls distinct at apex to body whorl. Upper and lower margins of slitband marked with very clear lines of orange colour. Shell base distinctly convex and rather 786 Bulletin of Marine Science [15(4)

FIGURE 32. Mikadotrochus salmianus (Rolle). Specimen in the U. S. National Museum; photographs courtesy of the Smithsonian Institution (x 0.7 approx.).

smooth. Columella thick, stout and callus pad thick and obsolete in its outer margin. Granules of costae on whorl obsolete." Thus we see that the "upper and lower margins of slitband [are] marked with very clear lines of orange colour" in schmalzi, and in salmiana "fasciola liris 2 distinctioribus rufts marginata." The "shell base (is] distinctly convex" in schmalzi, and Rolle described salmiana as "basi convexus." In schmalzi the "columella [is] thick, stout" and in salmiana "margo columellaris incrassatus." "The granules of costae on 1965] Bayer: Pleurotomariid Gastropods 787

FIGURE 33. Mikadotrochus salmianus (Rolle). Hypotype of Mikadotrochus schmaLzi Shikama (Habe, 1962), in the collections of Kyoto University. Photo- graphs courtesy of Dr. T. Kuroda. whorl [are] obsolete" in schmalzi and in salmiana "die Skulptur ist nicht so stark gekorneIt, sondern fast glatt" [in comparison with beyrichii]. The specimen from Kashiwajima in the U.S. National Museum is undoubtedly salmianus and it likewise agrees in all important features with Shikama's description of schmalzi. Regrettably, I must conclude, as Abbott (in Wagner & Abbott, 1964) also has done, that M. schmalzi Shikama =P. salmiana Rolle. It is impossible to draw a definite conclusion as to the identity of the specimen alleged to be salmiana illustrated by Shikama & Horikoshi (1963) because of the rear aspect shown, but it 788 Bulletin of Marine Science [15(4) very much resembles P. hirasei; in any event, it hardly could be true salmianus.

PRELIMINARY INVESTIGATIONS OF SCULPTURAL CHARACTERS In view of the fact that sculptural characters have systematic value in several groups of gastropods, and that the sculpture of pleurotomarians is of a regular, closely repetitive nature that allows reasonably accurate measurement, several ways of counting, analyzing and interpreting such repetitive shell characters were attempted. The samples available are admittedly inadequate to furnish any significant or conclusive data. The accompanying figures show graphically the results of measurements of P. quoyanus (2 specimens), P. gemma (2 specimens), P. lucaya (1 specimen), and P. midas (1 specimen). They must be considered only as examples of how pleurotomarian shells might be subjected to analysis· if larger samples could be obtained. Certainly, differences between the species are evident, but differences between specimens are evident also. The number of spiral cords on the base, and above and below the slit, is taken to be a significant character and is assumed to correspond closely for each species at any given shell size. The sculpture generated in connection with growth of the shell may be influenced by external conditions but nevertheless may be expected to show features characteristic of each species. Two kinds of counts of axial sculpture were made: (1) the number of axial riblets in a given uniform distance (1 cm) along the whorl, and (2) the number of riblets in a distance having a constant relationship (one tenth) to the circumference of the whorl, which was treated as a circle having the sutural diameter of the whorl. Obviously, the first of these measurements is useful only on the larger whorls and reflects any changes in frequency of the axials in the course of growth. The second can be employed even for the smaller whorls, and shows the relationship of the frequency of riblets to the size of the whorl. The axial sculpture does not remain unchanged as the shell grows. The riblets formed on the first whorl of the teleoconch are very fine, as the shell has a diameter of only about 1.5 mm at this stage. Thus it has a circumference of a little less than 5 mm, and over 55 riblets per cm. The riblets grow larger and more widely spaced as the shell increases in size, up to a point, after which there is very little change. Therefore, the first type of count will increase initially and then level off, whereas the second will continue to increase. The number ofaxials per centimeter plotted against the diameter of each whorl (Fig. 34A) shows the frequency at progressive stages of growth and, presumably, the point at which the rib1ets attain definitive size and frequency. The number ofaxials in one-tenth of the circumference plotted against the diameter of the whorl shows the relative frequency of the axials """ 1965] Bayer: Pleurotomariid Gastropods 789

=ON

...•= =ON 790 Bulletin oj Marine Science [15(4)

=ClO E

=•....

o =N

ClO=

•.... en "" 1965] Bayer: Pleurotomariid Gastropods 791 at progressive stages in growth (Fig. 34B), and plotted against the length of the sector will show changes in frequency relative to the size of the shell at progressive stages in growth. Features not related to sculpture but which nevertheless may prove valuable are the increase in diameter per revolution, and the changes in in- cremental angle of the spire (Fig. 35). GEOGRAPHICALDISTRIBUTION The Recent species of pleurotomarians now known are distributed as follows: West Indies (6) Japan (6) East Indies (1) South Africa (1) E. adansonianus E. rumphii E. rumphii P. african us P. amabilis P. hirasei P. gemma, n. sp. P. teramachii P. [ucaya, n. sp. P. "teramachii" P.quoyanus M. beyrichii P. midas, n. sp. M. salmianus This tabulation demonstrates why Japan has often been considered the center of pleurotomarian distribution. However, viewed in the light of ( 1) known distribution of other invertebrates, including gastropods, (2) the extent of faunal investigations in tropical marine waters, and (3) recent discoveries of pleurotomarians in the Western Atlantic, it seems likely that the vast Indo-Australian region has so far yielded only one specimen of one species because it is inadequately explored. In all probability several more pleurotomarian species inhabit that rich faunal area. The capture of pleurotomarians is for the most part an infrequent occurrence even in well explored regions. Only four complete specimens (three alive) and three fragments have been taken in over 500 bottom trawls made in the Western Atlantic by ships of the Institute of Marine Science. The Coast Survey steamer BLAKEwas somewhat more successful, but the ALBATROSS-which made thousands of stations, a very large number of them in pleurotomarian areas-obtained even fewer. Thus, it appears that these animals are found only by long and intensive exploratory dragging with a diversity of apparatus, especially on rough bottom between 50 and 300 fathoms, and it is not to be expected that many specimens will soon be found in the Indo-West Pacific even though it is likely that several more species occur there. In fact, the comments made by Rolle in 1899 (p. 164) have not only been borne out, but they remain as timely now as they were 66 years ago: "Ich glaube bestimmt, dass damit noch lange nicht aIle noch lebend existirende Pleurotomarien erschopft sind. Die Tiden der Meere mogen mit anderen uns noch ganzlich unbekannten Konchylien auch noch manche neue Pleurotomaria enthalten, die-wenn Dicht durch Tiefseeforschungen-nur durch Zufall an das Tageslicht kommt." 792 Bulletin of Marine Science [15(4)

SUMARIO NUEVOS GASTER6PODOS PLEUROTOMARIDOS DEL ATLANTICO OCCIDENTAL, CON UN SUMARIO DE ESPECIES RECIENTES La primera especie perteneciente a la epoca Reciente de la familia Pleu- rotomariidae, bien conocidos f6siles de los depositos Paleozoico y Mewsoi- co, fue descrita en 1856. Se reeoleeto cerca de la isla francesa de Guadalupe en las Antillas. Una segunda especie perteneciente a dicha epoca Reciente fue descubierta cinco alios mas tarde, tambi6n en las lndias Oeeidentales. Durante el siglo siguiente, se encontraron siete especies adicionales: cinco en el Jap6n, una en las Molucas y una en Africa del Sur, por 10 que pareda poder deducirse que las aguas japonesas eran las mas ricas en pleurotomarios. Sin embargo, en 1963, el Gerda, barco dedicado a investigaciones cientificas del Institute of Marine Science, colect6 una tercera especie para el Atlantico Hamada Mikadotrochus amabilis (Bayer, 1963). En 1965, como result ado de las operaciones de rastreo a profundidad efectuadas por el Gerda, se han obtenido dos nuevas especies para el AtUmtico y colec- ciones' privadas han aport ado otra mas. Estas tres especies, descritas ahora bajo el nombre de Perotrochus midas, P. lucaya y P. gemma, hacen un total de seis especies conocidas para el Atlantico Occidental; el eual, en conse- cuencia, es tan rico en especies como 10 son las aguas japonesas. Ademas, parece muy probable que se descubran otras nuevas especies a medida que las regiones del mundo poco exploradas, como el Indo-Pacifico tropical, se investiguen por medio de operaciones de draga y rastreo en fondos apro- piados entre las 25 y 300 brazas de profundidad. Perotrochus midas tiene una concha grande, espectacular, que se rela- ciona' con la forma japonesa P. teramachii. La concha es delgada y ligera, de color amarillo rosaceo, con una iridiscencia naearada que se ve a traves de la capa de poreelana semitransparente. La escultura esta farmada por cordones axiales espirales que se elevan como cuentas (= pequefias promi- nencias) en las intersecciones. El rasgo mas aparente de la concha es la espira, redonda, en forma de cupula, que no puede detinitivamente decIa- rarse normal ya que s610 se conoce un ejemplar. Perotrochus lucaya es una especie con concha parecida a la de P. quoyanus, pera con espiras regulares, casi ortoconoides, no constrefiidas en las suturas y de muy tina escultura reticular. El color de la concha es blanque- cino marcado con !ineas axiales de color beige amarillento palido. EI ejemplar unico tiene 8 vueltas y parece no estar completamente desarro- llado. Perotrochus gemma es igual que P. quoyanus en tamafio, tracoide con las suturas poco constreliidas. Las marcas de color son llneas axiales cons- picuas de un color rosaceo 0 rajo anaranjado, parecida en matiz al japones P. hirasei. 1965] Bayer: Pleurotomariid Gastropods 793 Se revisan las otras especies conocidas hasta el presente. Se incluyen £oto- graflas de (1) el holotipo y tres ejemplares de P. quoyanus; (2) el paratipo de P. amabilis; (3) el hipotipo de OaII de Entemnotrochus adansonianus y un ejemplar pequeno recolectado por el Gerda; (4) el holotipo de P. rumphii y un ejemplar pequeiio-destruido durante la Segunda Guerra Mundial -del Jap6n; (5) un ejemplar de P. africanus del U.S. National Museum; (6) el holotipo de P. teramachii; (7) un ejemplar japones identificado incorrectamente como P. teramachii pero que en realidad representa una especie no descrita; (8) Perotrochus hirasei de la colecci6n privada de la Ora. H. B. Owre; (9) el hipotipo de Mikadotrochus beyrichii del Insti- tuto Real de Historia Natural de Bruselas, y el ejemplar del U.S. National Museum; y (10) el ejemplar de M. salmianus del U.S. National Museum y uno identificado como M. schmalzi Shikama del Instituto Geol6gico de la Universidad de Kyoto, que es sin6nimo de M. salmianus. Se discute brevemente la clasificaci6n de los Pleurotomarios de la epoca Reciente y se dan las caracteristicas de los generos. Se presenta una clave de las especies del Atlantico Occidental. Se discute la utilidad en potencia del uso de las caracteristicas de la escultura y las medidas de la concha como caracteres taxon6micos.

LITERATURE CITED ABBOTT,ROBERTTUCKER 1954. American seashells. D. Van Nostrand Co., New York, xiv + 541 pp., 100 text-figs., 40 pIs. AGASSIZ,ALEXANDER 1888. Three cruises of the United States Coast and Geodetic Survey steamer "Blake" in the Gulf of Mexico, in the Caribbean Sea, and along the Atlantic coast of the United States, from 1877 to 1880. Volume 2. Bull. Mus. compo Zool. Harvard, 15: 220 pp., 545 text-figs. BAYER,FREDERICKM. 1963. A new pleurotomariid gastropod trawled in the Straits of Florida by R/V GERDA.Bull. Mar. Sci. Gulf & Carib., 13: 488-492, fig. 1. BOUVIER,E. L. ANDH. FISCHER 1899. Reports on the results of dredging ... in the Gulf of Mexico and the Caribbean Sea, and on the east coast of the United States, 1877 and 1880 ... XXXVIII. Etude monographique des pleurotomaires actuels. Bull. Mus. compo Zoo!. Harvard, 32 (10): 193-249 text-figs. A-F, pIs. 1-4. Also in J. Conchyliol., 47: 77-151, pIs. 4-7. Cox, L. R. 1960. General characteristics of Gastropoda. In: Moore, R. C. (Ed.), Treatise on invertebrate paleontology. Part I. Mollusca, 1: 84-169. Geo!. Soc. Amer. and Vniv. Kansas Press, xxiii + 351 pp., 304 figs. CROSSE,JOSEPHCHARLESHIPPOLYTE 1882. Les pleurotomaires de l'epoque actuelle. J. Conchylio!., 30: 5-22, pI. 1. CROSSE.JOSEPHCHARLESHIPPOLYTEANDP. FISCHER ]861. Observations sur Ie genre Pleurotomaire, et description d'une deuxieme espece vivante appartenant au meme genre. J. Conchyliol., 9: 155- 167. pI. 5. 794 Bulletin of Marine Science [15(4)

DALL, WILLIAM HEALEY 1881. Reports on the results of dredging ... in the Gulf of Mexico, and in the Caribbean Sea, 1877-79, by the United States Coast Survey steamer "Blake" ... XV. Preliminary report on the Mollusca. Bull. Mus. compo Zool. Harvard, 9 (2): 33-144. 1889. Reports on the results of dredging ... in the Gulf of Mexico (1877- 78) and in the Caribbean Sea (1879-80), by the U. S. Coast Survey steamer "Blake" ... XXIX. Report on the Mollusca. Part 11.- Gastropoda and Scaphopoda. Bull. Mus. compo Zool. Harvard, 18: 1-492, pIs. 10-40. 1889a. A preliminary catalogue of the shell-bearing marine mollusks and brachiopods of the United States, with illustrations of many of the species. Bull. U. S. Nat. Mus., 37; 201 pp., 74 pIs. [Reprint, 1903: 232 pp., 95 pIs.] DAUTZENBERG, P. AND H. FISCHER 1898. Note sur Ie Pleul'otomaria beyrichi. J. Conchyliol., 46: 218-224, pI. 11. FISCHER, P. 1885. Manuel de conchyliologie et de pah~ontologie conchyliologique. His- toire naturelle des mollusques vivants et fossiles. Fasc. 9; 785-896. Libraire F. Savy, Paris, xxiv + 1369 pp., 1138 figs., 23 pIs. (1887). FISCHER, P. AND A. C. BERNARDI 1856. Description d'un pleurotomaire vivant. J. Conchyliol., 5: 160-166, pI. 5. FRETTER, VERA 1964. Observations on the anatomy of Mikadotrochus amabilis Bayer. Bull. Mar. Sci. Gulf & Carib., 14 (I): 172-184, figs. 1-6. H~BE, TADASHIGE 1961. Zoku genshoku Nihon kairui zukan. (Coloured illustrations of the shells of Japan, II.) Hoikusha, Osaka, [iv]+ix+[3]+182 pp., 66 color plates. 1962. Idem. Second edition, with nomenclatural changes. HILGENDORF, F. 1877. [Presentation of a specimen of a new Pleurotomaria.] Sitzungsbericht der Gesellschaft naturforschender Freunde vom 20. Marz 1877, 3: 72-73. HIRASE, SHINTARO 1934. A collection of Japanese shells with illustrations in natural colours. Matsumura Sanshodo, Tokyo. 14+2+129 pp.+217 pIs. [Several subsequent printings; a revised edition, edited by I. Taki, appeared in 1951.J HIRASE, Y. 1907. Catalogue of marine shells of Japan. To be had of Y. Hirase. Kara- sumaru, Kyoto, Japan, [ii] +49 pp., 3 pIs. KIRA, TETSUAKI 1954. Genshoku Nihon kairui zukan. [Coloured illustrations of the shells of Japan.J Hoikusha, Osaka, [x] + 172 +24 pp., including 67 color plates. 1961. Genshoku Nihon kairui zukan. Zoho kaitei han. (Coloured illustrations of the shells of Japan. Enlarged and revised edition.) Hoikusha, Osaka, [viiJ + vii + [2J + 239 pp., 71 color plates. 1962. Shells of the western Pacific in colour. Hoikusha, Osaka, 224 pp., 72 pis. 1965] Bayer: Pleurotomariid Gastropods 795

KNIGHT, 1. BROOKES. et at. ] 960. Systematic descriptions [Archaegostropoda]. In: Moore, R. C. (Ed.), Treatise on invertebrate paleontology. Part I. Mollusca, 1: 169-331. Geol. Soc. Amer. and Univ. Kansas Press, xxiii + 351 pp., 304 figs. KURODA, TOKUBEI 1936. Arata ni bosan to shide kiroku seraruru okinaebisu isshu ni tsuite. [On a species of okinaebisu (=Pleurotomaria) recorded as new to Japanese waters.] Kairuigaku zasshi Venus [Venus, the Japanese Journal of Malacology], 6 (4): 250-254, figs. 23-25 and fig. on title page of volume. ]955. A new Pleurotomaria from Japan with a note on a specimen of P. rumphii Schepman collected from Taiwan. Venus, 18 (4): 211-221, pis. 8-9. LINDHOLM, W. A. 1927. 0 Pleurotomaria beyrichi Hilgendorf (Gastropoda) v Kollektsiiakh Zoologicheskogo Muzeia AN s zametkoi 0 rode Pleurotomaria s. lat. (Sur les Pleurotomaria beyrichi Hilgendorf (Gastropoda) dans les collections du Musee Zoologique avec une notice sur Ie genre Pleuro- tomaria s. lat.) Doklady Akad. Nauk SSSR, 24: 409-414. VON MARTENS, E. ] 880. Pleurotomaria Beyrichi Hilgendorf. In Conchologische Mittheilungen als Fortsetzung der Novitates Conchologicae herausgegeben von Dr. E. von Martens, professor in Berlin, vol. ] :33-34, pI. 7. Verlag von Theodor Fischer, Kassel, viii+iv+ 101 pp., pis. 1-18. (1881.) NUTTING, CHARLES CLEVELAND 1919. Barbados-Antigua Expedition. Narrative and preliminary report of a zoological expedition from the University of Iowa to the Lesser Antilles under the auspices of the Graduate College. Univ. Iowa Stud. nat. Hist., 8 (3): 274 pp., 50 pis. OKADA, Yo 1960. Genshoku dobutsu daizukan. (Encyclopaedia Zoologica illustrated in colours.) III. Hokuryukan, Tokyo. [vi] + 200 + 28 + 38 pp., 91 pis. PILSBRY, HENRY AUGUSTUS 1890. Stomatellidae, ScissureIlidae, Pleurotomariidae, Haliotidae, Addisoni- idae, Cocculinidae, FissureIlidae. In: Manual of conchology, struc- tural and systematic. Volume 12. Concho logical Section, Academy of Natural Sciences, Philadelphia, 321 pp., 65 pis. 1903. A new Pleurotomaria. Nautilus, 17 (3): 36. REEVE, LOVELL A. ] 874. Monograph of the genus Pleurotomaria. In: Conchologia Iconica: or illustrations of the shells of molluscous animals, Vol. 19. L. Reeve & Co., London, 2 unnumbered pp. and 1 pI. ROLLE, HERMANN 1899. Eine neue Pleurotomaria. Nachrichtsblatt der deutschen Malako- zoologische Gesellschaft, 31: 62. 1899a. Pleurotomaria salmiana m. Nachrichtsblatt der deutschen Malako- zoologische Gesellschaft, 31: 161-164, 1 pI. SCHEPMAN, MATHIAS M. 1879. Eine neue recente Pleurotomaria. Tijdschr. Ned. Dierk. Vereen., 4: 162-167. 1882. Conchyliologische Bijdragen. Tijdschr. Ned. Dierk. Vereen, 6: 20- 23, pI. 2. figs. 1-3. 796 Bulletin of Marine Science [15(4) SCHMALZ,C. 1901. Die Gattung Pleurotomaria. In: W. Kobelt (Ed.), Systematisches Conchylien-Cabinet von Martini und Chemnitz, 6 (Ie): 1-104, pis. 1-16. SHIKAMA,TOKIO 1961. Choshi okisan chojagai salmiana ni tsuite. (On Mikadotrochus salmiana found off Choshi, East Japan.) Kairuigaku zasshi Venus (Venus, the Japanese Journal of Malacology), 21 (4): 500-506, pIs. 28-29. 1964. Genshoku Zukan. Zoku sekai no kai. (Selected shells of the world illustrated in colours, II.) Hokuryu-kan, Tokyo, [x] +212 pp., 245 text-figs., frontispiece + 70 color plates. SHIKAMA,TOKIOANDMASUOKIHORIKOSHI 1963. Genshoku Zukan. Sekai no Kai. (Selected Shells of the world illustrated in colours.) Hokuryu-kan, Tokyo, [x] + 154 pp., 211 text-figs., 102 eolorplates. SOWERBY,G. B. 1831. Pleurotomaria. In: The genera of Recent and fossil shells, for the use of students in conchology and geology, p. 196. G. B. Sowerby, Lon- don, 274 Ivs., 264 pis. (1821-1834.) . 1884. Pleurotomaria, Defrance. In: Thesaurus Conchyliorum, 5 (2): 183- 185, pis. 491-492. TAKI,IsAO 1951. A handbook of illustrated shells in natural colors from Japanese islands and their adjacent territories by Shintaro Hirase (1884-1939) revised and enlarged. Bunkyokaku, Tokyo, xxiv [xxx] pp., 134 pis., 46 pp. TOMLIN, J. R. LE B. 1948. A new species of Pleurotomaria. J. Conchol., 23: 2, pI. 1. TURNER,RUTH 1961. Pleurotomariidae in Bermuda waters. Nautilus, 74 (4): 162-163. WAGNER,ROBERTJ. L. ANDROBERTTUCKERABBOTT 1964. Van Nostrand's standard catalogue of shells. D. Van Nostrand Co., Princeton, New Jersey, ix+ 190 pp. text-figs. WOODWARD,H. 1885. On Recent and fossil Pleurotomariae. Geol. Magazine, N. S. 1885, Decade III, 2 (10): 433-439, pI. 11. WOODWARD,M. F. 1901. The anatomy of Pleurotomaria beyrichii Hilg. Quart. J. micro Sci., 44: 215-268.