235
I MANGIAGALLI has given his large the Istituto Ostetrico-Ginecologico ,f Milan, which bears his name. The i addition to 10,000 bound volumes, unbound treatises and rare complete SKULL AND SKELETAL REMAINS OF A ttific reviews. tents Dornalo, submarine specialists, RUMINANT OF THE PREPTOCERAS the course of the present season the ine views in the Medit!!rranean, in EUCERATHERIUM GROUP >m 40 to 50 meters, with the help of ts which will carry one man and a FROM THE )icture projector. Their purpose is submarine life in its natural sur McKITTRICK PLEISTOCENE, CALIFORNIA acting to the lighted area all species these depths. These views will be educational films. The work will to the tropical regions. BY Zionist Organization of America, CHESTER STOCK AND E. L. FURLONG ah, voted recently to expend $609, d health work in Palestine, most of Balch Graduate School of the Geological Sdcnces support the Hadassah Medical Or- California Institute of Technoloc . country. In addition to that bud Pasadena, California tion voted to raise $100,000 from ical service in Palestine. The need Contribution No. 9 in Palestine is considered urgent. pressed its gratitude in a unanimous UNIVERSITY OF CALIFORNIA PUBLICATIONS tan and Mrs. Straus, of New York, BULLEiiN 01' THE DEPARTMFNT 01' GEOLOGICAL SCIENCES : $250,000 for a health center in Volume 16, No. 10, pp. 409-434, plates 60-63, 5 figures in text
rY AND EDUCATIONAL NOTES 11nting to $550,000 have been made hool of the University of Chicago; .rection and equipment of a building he Gertrude Dunn Hicks Memorial, irated as an orthopedic hospital, and :. Louis H. Kuppenheimer to estab t fund to be known as the Louis B. :uppenheimer Foundation. The in id for teaching and research in the hthalmology. B. ZuKER, head of the department of University of Dubuque since 1921, d acting president of that institution )tember 1, when the resignation of UNIVERSITY OF CALIFORNIA PRESS W ettstone, D.D., took effect. BERKELEY, CALIFORNIA w ARD, director of the Davis branch 1927 SKULL AND SK RUMINANT o: EU CERA'
McKITTRICK PL
CHESTER S UNIVERSITY OF CALIFOR.' Volume 16, No. 10, pp. 409-434, pla~ es 60-63, 5 figures in text Issued January 25, 1927 Introduction ...... Description of material ...... Preptoceras? cf. sincZairi Fm Resume of characters exhibitec UNIVERSITY OF CALIFORNIA. PRESS Relationship of Preptoceras an BEll.K!!:LEY, CALIFORNIA. Explanation of plates ...... CAMBRIDGE UNIVERSITY PRESS I LONDON, ENGLAND In studies of the Pleist the ruminant genera Pre: be regarded as characteris of the State. Although t: Brea is unusually comple ungulates has been found asphalt deposit of McKi occurrence in Los Angel, fornia, the discovery of Charles H. Sternberg ad1 of mammals recorded fro The recognition of a therium group in the M that a faunal difference La Brea stages of the P: for by a geographic sel?~ member of this group an 1 Merriam, J. C., and St1 cation 347, pp. 37-42, 1925. SKULL AND SKELETAL REMAINS OF A RUMINANT OF THE PREPTOCERAS EUCERATHERIUM GROUP FROM THE McKITTRICK PLEISTOCENE, CALIFORNIA BY PUBLICATIONS CHESTER STOCK A..."ID E. L. FURLONG · GEOLOGICAL SCIENCES ~s 60-63, 5 figures in text i, 1927 CONTENTS PAGE Introduction --- -·---·························· ·· ·····-······-·· ·------·············-····-·················-········- 409 Description of material ---- ·····················-·······--························································-·· 410 Preptoceras? cf. sinclairi Furlong ····················-···-·--· --"-·····-.. ·············-················ 410 Resum~ of characters exhibited by McKittrick material ...... 425 tNIA PRESS Relationship of Preptoceras and Euceratherium ...... 425 ORNIA Explanation of plates ·······-··--·········· ································--·-··-----·-·······----···········'······-- 438 l.'Y PRESS INTRODUCTION rnD In studies of the Pleistocene mammalian assemblages of California the ruminant genera Preptoceras and Euceratheriuni have come to be regarded as characteristic of the faunas known Iriom cave deposits of the State. Although the record of mammalian life at Rancho La Brea is unusually complete, it is noteworthy that no trace of these ungulates has been found. With continuation of excavations in the asphalt deposit of McKittrick, Kern County, situated between the occurrence in Los Angeles and the cave deposits of northern C~li fornia, the discovery of remains of one of these ruminants by Mr. Charles H. Sternberg adds a new and important member to the list of mammals recorded from this horizon. The recognition of a representative of the Preptoceras-Eucera therium group in the McKittrick fauna lends strength to the belief that a fauna! difference exists between the McKittrick and Rancho La Brea stages of the Pleistocene which cannot be wholly accounted for by a geographic sel?aration of the deposits. The occurrence of a member of this group and of a llama1 (L(fJma stevensi) at McKittrick 1 Merriam, J. C., and Stock, C., Carnegie Institution of Washington, Publi cation 347, pp. 37-42, 1925. 410 University of California Publications in Geological Sciences [Vol.16 1927] Stock-Furlong: PreJ and the absence of these mammals at Rancho La Brea strongly suggest to the long diameter is gr that similar environmental conditions did not prevail at the two right side of the skull th« localities and may furnish evidence in support of the view that the from the side of the crani two faunas were not contemporaneous. A solution of the problem of belonging to the outer ha time relationship of the two asphalt assemblages appears to possess ently belong to the right fundamental importance in any attempt to establish a faunal succes tions cannot now be conne sion for the Pleistocene of western North America. in the McKittrick skull. The illustrations have been prepared by Mr. John L. Ridgway while toward the outer enc of the Carnegie Institution of Washington. is marked by ridges and evidence on the lower pos1 of the horn cores approacl distinctly more so than in DESCRIPTION OF MATERIAL Pleistocene of Texas, anc PREPTOCERAS 7 cf. SINCLAIR! Furlong verse measurement taken Locality.-McKittrick Pleistocene asphalt deposits, U. C. loc. 7139. No. lower borders of the horr 27118, U. C. Mus. Pal. Vert. Coll. Euceratherium, and is co: Important differences The materials available include a fragmentary skull with incom have been generally re plete horn cores, complete cheek-tooth series of one side, and a nearly Euceratherium. In Prei complete ramus with incisors and canine of the lower dentition situated farther apart a· missing. The posterior cannon bones, astragalus, cubo-navicular and latter genus the horn cor phalangeal elements (no. 27119 Mus. Pal. U. C.) are presumably to a point, measured from be referred to the individual represented by the skull. posterior or upper surfac In no. 2711~, all the permanent premolars and molars are in back than in Preptocer~ function and M~ is only slightly worn. Judging from the state of the occiput, the upper b wear of the teeth, no. 27118 belonged to an older individual than those farther removed from th of Preptoceras represented by specimens nos. 8896 and 1109 U. C. in Preptooeras. In Pre Mus. Pal. Vert. Coll. from Samwel Cave, but was not so old as that from the skull than in represented by the type specimen of Euceratherium, no. 8751 U. C. specimen the horn core Mus. Pal. Vert. Coll. The individual from the McKittrick Pleistocene but becomes circular nci resembles in size Preptoceras sinclairi and is slightly larger than the anterior surface of the type of Euceratherium collinum, both from the Samwel Cave deposit. Preptoceras is flattened · Horn cores.-The horn cores in no. 27118 have a shape and curva In no. 27118 from :N. ture, in so far as these characters can be determined from the struc face of the proximal por tures preserved, like those in the type specimen of P. sinclairi. Some in no. 8896. The great1 resemblance is seen when the McKittrick form is compared with the the orbit reached by thE type of Euceratherium. The horn cores are certainly much stouter in its backward and ou than those of the type of Euceratherium, no. 8751, in which respect that in Euceratherium. they are like those in Preptoceras. At the base of these structures than in the latter genu: the long diameter ( anteroposterior) through the core is close to that removed from the orbit in the type of Preptoceras, no. 8896, but the diameter taken normal : in Geological Sciences [Vol. 16 1927] Stock-Furlong: Preptoceras-Euceratheriwm from McKittrick 411 1cho La Brea strongly suggest to the long diameter is greater in the McKittrick specimen. On the did not prevail at the two right side of the skull the horn core extends approximately 90 mm. mpport of the view that the from the side of the cranium. Two separate sections of a horn core, A. solution of the problem of belonging to the outer half, are present in the collection and appar .emblages appears to possess ently belong to the right side of no. 27118. Unfortunately, the sec to establish a fauna! succes tions cannot now be connected with the basal portion of the horn core in the McKittrick skull. The horn core is :flattened near the base h America. ' d by Mr. John L. Ridgway while toward the outer end it has a circular cross-section. The surface ton. is marked by ridges and vascular canals, which are particularly in evidence on the lower posterior and anterior sides. The basal portions of the horn cores approach each other more closely than in P. sinclairi, distinctly more so than in Preptoceras mayfieldi from the Rock Creek iA.TERIA.L Pleistocene of Texas, and less so than in Euceratherium. A. trans LAIR! Furlong verse measurement taken across the frontals and between the outer lower borders of the horn cores is much greater in no. 27118 than in deposits, U. C. loe. 7139. No. Euceratherium, and is comparable to that in P. sinclairi. Important differences in size and in curvature of the horn cores agmentary skull with incom have been generally regarded to exist between Preptoceras and ries of one side, and a nearly Euceratherium. In Preptoceras the horn cores are stouter and are iine of the lower dentition situated farther apart at the base than in Euceratherium. In the ~tragalus, cubo-navicular and latter genus the horn core in its backward and outward curve reaches 11. U. C.) are presumably to a point, measured from the dorsoposterior rim of the orbit to the l by the skull. • posterior or upper surface of the horn core, which is distinctly farther remolars and molars are in back than in Preptoceras. When measured vertically in the plane of Judging from the state of the occiput, the upper border of the horn core in Euceratherium is ln older individual than those farther removed from the ventral border of the occipital condyle than ts nos. 8896 and 1109 U. C. in Preptoceras. In Preptoceras, the horn cores extend farther out e, but was not so old as that from the skull than in the type of Euceratheri1im. In the latter iceratherium, no. 8751 U. C. specimen the horn core is elliptical in cross-section near the base •m the McKittrick Pleistocene but becomes circular near the outer end. A.s noted by Furlong, the' 1d is slightly larger than the anterior surface of the proximal two-thirds of the horn core in om the Samwel Cave deposit. Preptoceras is :flattened while the posterior surface is strongly convex. 7118 have a shape and curva In no. 27118 from McKittrick, the :flattening of the anterior sur e determined from the struc- face of the proximal portion of the horn core is better expressed than 0ecimen of P. sinclairi. Some in no. 8896. The greatest distance behind the dorsoposterior rim of k form is compared with the the orbit reached by' the posterior or upper surface of the horn core s are certainly much stouter in its backward and outward curve .from the skull is comparable to ~, no. 8751, in which respect that in Euceratherium. Since the proximal portion is much larger the base of these structures than in the latter genus, the anterior or lower surface is not so far )ugh the core is close to that removed from the orbital rim as that in the type of E1teeratherium, Lt the diameter taken normal Stock-Furlong: P 412 University of California Publications in Geological Sciences [Vol.16 1927) and the distance is more nearly equal to that in the type of Prept~ decide~ly larger, in whi ceras. A measurement taken vertically in the plane of the occiput the McKittrick specimer from the inferior border of the occipital condyle to the superior in a direction transvers border of the horn core gives a height which exceeds that in Prepto~ no. 2337 differs quite ceras and closely corresponds to that in Euceratherium. distal third does not ap] The McKittrick species appears to resemble Preptoceras in some from McKittrick, and tb characters of the horn cores, while in other characters it is like the proximal portion ex Euceratherium. The resemblance to Preptoceras is seen chiefly in the forward, than in no. 27 size and shape of the proximal portion of the horn core and in the extent to which this portion reaches outward and backward from the skull before curving forward. With orientation of the separate distal sections in the McKittrick specimen, a curvature is given to the horn core which presumably is like that in Preptoceras, although suggestive at least of that seen in Euceratherium. While the lower anterior border of the horn core in no. 27118 reaches in its outward and backward curve a point behind the orbital rim comparable to that reached in Preptoceras, the opposite border is much farther removed, in which respect no. 27118 is more like Eucera therium. The upper portion of the horn core also reaches farther above the inferior border of the condyle, measured in the plane of the occiput, as in Euceratherium. Furthermore, the horn cores are more • closely placed than in Preptoceras, less so than in Euceratherium. It appears reasonable to suppose that in a skull like this one from McKittrick, with, however, completely preserved horn cores, a resemblance to Euceratheriiim would be more clearly indicated. Pos sibly no. 27118 belongs to a eucerathere. On the other hand there may be drawn, perhaps, from the comparisons which have been made, an inference that the characters presented in the horn cores which distinguish Preptoceras from Euceratherium are not sharply defined and are subject to considerable variation within a single group. Fig. 1. Euceratherim A horn core in the paleontological collections of the University of Coll. Two views with er~ County, California. California obtained many years ago from gravels of the Klamath River, thirty feet below water level, at Gottville, Siskiyou County, Presuming that tl California, is of interest in the present study since it probably belongs been rightly identifie to a member of the Preptocer·as-Euceratherium group. This specimen, variation in size of he no. 2337, U. C. Mus. Pal. Vert. Coll., has been generally regarded as latter character Euc belonging to Euceratherium, although a description of the material other hand, no. 233~ has never been published. No. 2337, shown in figure 1, has a shape and the type of Preptoce curvature very much like that in the type specimen of Euceratherium. tunately, the horn CO' No. 2337 differs, however, from the horn core in no. 8751 in being well preserved to pe· 413 i Geological Sciences [Vol. 16 1927] Stock-Furlong: Preptoceras-Euceratherium from McKittrick ;hat in the type of Prepto decide~ly larger, in which respect it resembles more the horn core of n the plane of the occiput the McKittrick specimen. The proximal half is distinctly compressed .1 condyle to the superior in a direction transverse to the long diameter, and in this character ich exceeds that in Prepto no. 2337 differs quite noticeably from the McKittrick form. The !tceratherium. distal third does not appear to have been so large as that in no. 27118 emble Preptoceras in some from McKittrick, and the outer posterior surface is flatter. In no. 2337 other characters it is like the proximal portion extends farther out from the base before turning :oceras is seen chiefly in the forward, than in no. 27118. E the horn core and in the 1rd and backward from the tation of the separate distal vature is given to the horn toceras, although suggestive he horn core in no. 27118 e a point behind the orbital :eras, the opposite border is . 27118 is more like Eucera- 1 core also reaches farther ieasured in the plane of the re, the horn cores ar.e more than in Ettceratherium . .t in a skull like this one ily preserved horn cores, a tore clearly indicated. Pos- On the other hand there sons which have been made, • :d in the horn cores which um are not sharply defined within a single group. Fig. 1. Euceratherium sp. Right horn core, no. 2337 U. C. Mus. Pal. Vert. ections of the University of Coll. Two views with cross-sections; X 0.25. Klamath River, Gottville, Siskiyou County, California. m gravels of the Klamath Gottville, Siskiyou County, Presuming that the specimen from the Klamath River gravels has dy since it probably belongs been rightly identified as belonging to Eiweratherium, considerable -iu.m group. This specimen, variation in size of horn core is seen to exist in this genus, and in this been generally regarded as latter character Euceratherium may resemble Preptoceras. On the description of the material other hand, no. 2337 differs as much in shape and curvature from 1 in figure 1, has a shape and the type of Preptoceras as does the type of Eiweratherium. Unfor specimen of Euceratherium. tunately, the horn core in the skull from McKittrick is not sufficiently l core in no. 8751 in being well preserved to permit a decision as to the extent of similarity in 414 University of California Publications in Geological Sciences [Vol.16 1927) Stock-Furlong: Prt shape and curvature of horn core between no. 27118 and no: 2337. the teeth, belongs to an It appears within the range of possibility, however, to recognize a skulls, nos. 1009 and 27 greater resemblance between no. 27118 and no. 2337 than exists opening in no. 27118 occu between the latter specimen and the type of Preptoceras. ' not quite reach forward t Crarvium.-The frontals rise in their backward extent from the opening. Similar indent1 fronto-nasal suture to the horn cores. In side view of the skull therium, as might be exp• (pl. 61), this is expres.sed in an elevation of the forehead region some postnarial notch, no deci what like that in Preptoceras. The elevation is, however, not so pro on either side of the op nounced as in no. 1009 of Preptoceras from Samwel Cave, but appears University collections, in to be slightly more evident than in Euceratherium. Between the worn than in no. 271U orbital rims the frontals have a width similar to that in the type of broader and is situated Euceratherium and like that in the skull of P. sinclairi, no. 1009. The or in Eiiceratherium. 1 supra-orbital foramina are situated 33 mm. from the orbital rim. of this notch reaches di~ The orbits are distinctly less tubular and do not protrude so much narial notch, but does nc as in the living musk ox. The surface of the lachrymal is more skulls of Ovibos figured depressed than in the skulls of Preptoceras from the cave deposit. indentation is seen to m The difference may be ascribed to age, since the cave specimens belong the increase in age of tl to younger individuals than that from McKittrick. In the type of The palate in no. 27: Euceratherium, however, the-surface of the lachrymal is less depressed molars, is narrower th~ than in no. 27118, although the skull belongs to an older individual width is more like that than those of Preptoceras and that from McKittrick. In the basicranial re1 The forward portion of the skull is poorly preserved and the nasals no. 27118 from McKittr: are largely broken away. The position of the fronto-nasal suture Cave. There is also co1 appears to be slightly farther back than in Ovibos. The nasal indents the McKittrick specime the frontal to a greater extent than in the living musk ox. In no. ture are better shown in 27118, as in the skulls of Preptoceras from Samwel Cave, the maxil hence aff 6rd an opport lary eminence is situated above M!. In the musk ox this eminence is other bovid forms. In · situated above M~ . The infra-orbital. foramen has also a position relatively small ahd in farther forward than in Ovibos. The maxillopalatine suture appears narrower notch than i to extend forward to a point between the anterior ends of the second character, no. 27118 is superior molars. The postnarial notch is V-shaped and narrow, different in shape fro resembling that in Euceratherium. In no. 1009 of Preptoceras the element in Preptocercu notch is broader, but the difference in breadth may be due, at least the basioccipital is tra· in part, to the imperfect preservation of the borders. The notch is groove which broaden like that in no. 1009 and differs from that in Euceratherium in reach groove is present, whicl ing farther forward. In no. 27118 as in no. 1009, the posterior narial the basisphenoid make notch reaches forward to a point opposite the posterior lobe of M!!. is the same as that In the type of Ettceratherium, no. 8751, the anterior end of the notch Euceratherium. is opposite the posterior ends of the third superior molars. It should 2 Allen, J. A., Ontogen• be recalled, however, that no. 8751, judging from the state of wear of tematic review of the mu Hist., n.s., vol. 1, pt. 4, 1! Geological Sciences [Vol.16 1927] Stock-Furlong: Preptoceras·Euceratherium .from McKittrick 415 no. 27118 and no. 2337. the teeth, belongs to an older individual than those represented by , however, to recognize a skulls, nos. 1009 and 27118. On each side of the posterior narial ~ nd no. 2337 than exists opening in no. 27118 occurs an indentation of the palatine, which does f Preptoceras. ' not quite reach forward to a point opposite the anterior border of the 1ackward extent from the opening. Similar indentations are to be seen in no. 1009. In Eucera n side view of the skull therium, as might be expected from the more posterior position of the the forehead region some- postnarial notch, no decided indentation of the palatine is to be seen m is, however, not so pro on either side of the opening. In an adult skull of Ovibos in the Samwel Cave, but appears University collections, in which the permanent cheek teeth are more iratherium. Between the worn than in no. 27118 from McKittrick, the postnarial notch is Jar to that in the type of broader and is situated decidedly farther back than in Preptoceras P. sinclairi, no. 1009. The or in Euceratherium. The indentation of the palatine on each side m. from the orbital rim. of this notch reaches distinctly beyond the anterior end of the post do not protrude so much narial notch, but does not reach a point opposite M2. In the series of lf the lachrymal is more skulls of Ovibos figured and described by Allen, 2 the lateral palatine a.s from the cave deposit. indentation is seen to move backward relative to the tooth row with the cave specimens belong the increase in age of the individuals. :Kittrick. In the type of The palate in no. 27118, as measured between the second superior lachrymal is less depressed molars, is narrower than in skull no. 1009 of Preptoceras, and in igs to an older individual width is more like that of E?weratherium. [cKittrick. In the basicranial region there is considerable resemblance between y preserved and the nasals no. 27118 from McKittrick and the skulls of Preptoceras from Samwel tf the fronto-nasal suture Cave. There is also considerable resemblance in this region between Ovibos. The nasal indents the McKittrick specimen and Euceratherium. The details of struc e living musk ox. In no. ture are better shown in no. 27118 (fig. 2), than in the cave skulls and L Samwel Cave, the maxil hence afford an opportunity for closer comparison with Ovibos and ~ musk ox this eminence is other bovid forms. In the McKittrick skull the occipital condyles are amen has also a position relatively small ahd in ventral view are seen to be separated by a illopalatine suture appears narrower notch than is present in the cave skulls. In the latter ,nterior ends of the second character, no. 27118 is more like Ovibos. The basioccipital is quite is V-shaped and narrow, different in shape from that in Ovibos and closely resembles the '· 1009 of Preptoceras the element in Preptoceras and in Euceratherium. As in these forms, adth may be due, at least the basioccipital is traversed in its anteroposterior extent by a wide :he borders. The notch is groove which broadens posteriorly. In Symbos a narrow median n Euceratherium in reach groove is present, which broadens posteriorly. The angle (20°) which . 1009, the posterior narial the basisphenoid makes with the basioccipital in the vertical plane the posterior lobe of M2. is the same as that in Preptoceras from Samwel Cave and in i anterior end of the notch Euceratherium. :uperior molars. It should 2 Allen, J. A., Ontogenetic and other variations in ~he musk oxen, with a sys : from the state of wear of tematic review of the musk ox group, recent and extmct, Mem. Am. Mus. Nat. Hist., n.s., vol. 1, pt. 4, 1913. 1927] Stock-Furlong: 416 University of California Publications in Geological Sciences [Vol. 16 Oreamnos. In Ovis a On each side of the basisphenoid the posterior border of the squamosal fills the spa< alisphenoid descends more abruptly than in Ovibos. No. 27118 appears portion of the tympani to differ in this regard from no. 1009 and from the type of Eucera latter structure. In 0 therium, but the descending process of the alisphenoid may not be In the McKittrick spec completely preserved in the cave skulls. an open groove is pre The postglenoid process is small, comparable to that in no. 1009 process and the pos1 and in no. 8751 of Euceratherium. At the outer side of the process tympanic. No broad 1 is the large lower exit of the squamosal canal. The auditory capsules foramen lacerum post are smaller than in Ovibos. The tubular portion of the tympanic and the area is shorteu as compared with tha1 -t: l.a. +t:r: as in the cave skulls, a ridge, extending im from a small depress 27118 there are two occipital processes are base of this process i e.r.a.m.--- much as in Ovibos. The squamosal au skull (pl. 61). A lar1 • fossa. The position o The upper posterior i vascular f oramen. 1 Fig. 2. Preptoceras? cf. sinclairi Furlong. Basicranial region of right side extends backward be1 of skull, no. 27118 U. C. Mus. Pal. Vert. Coll., X 0.50. f.l.a + f.r., confluent posterior border of tl foramen lacerum anterius and foramen rotundum; f.o., foramen ovale; f.l.m., foramen lacerum medius (muscular process beneath this foramen has been broken men on the dorsal ~ away); f.l.p. foramen lacerum posterius; c.f. condylar foramen; sq.c., squamosal Presumably the pari canal; ex.a.m., external auditory meatus; s.f., stylomastoid foramen; t.ky., tympano-hyal pit; ms.p., mastoid process; pa.p., base of paroccipital process. crest of the occiput t McKittrick Pleistocene, California. in the Preptoceras. J. reaching outward to form the external auditory meatus is fuller than is absent in this speci: in Ovibos. The backward deflection of the external auditory meatus plane of the occiput • is distinctly less than in Ovibos and comparable to that seen in the roof posterior to the cave skulls of Preptoceras and Euceratherium. In Ovis and in In the type of P. si Oreamnos this deflection is even less than in Preptoceras. In Symbos, Euceratherium it is 1 according to Osgood, 3 the external auditory meatus is larger and less from supra-occipital deflected backward than in Ovibos. The tympano-hyal pit• is deep. of Preptoceras sincl Mandible.-The ramus of the mandible of no. 27118 is smaller Dentition.-ln no. 2~ than that in the musk ox with the inferior cheek-tooth series relatively inclusive) is longer relati large (see pl. 63). The greater forward extension of the ramus This proportionately grE evident when the superio beyond P 2 in Ovibos than in Preptoceras is occasioned by a greater lengthening of the symphyseal region in the former genus. The ramus The superior dental serie is noticeably swollen externally below the exposed posterior portion therium from Samwel c~ ence of a very small ac~ of M3, and relatively more so than in Ovibos. The posterior dental foramen is larger than in Ovibos, but the mental foramen is smaller between the anterior anc and without a well defined groove extending anterior to it, as in the superior molars and stat• , living genus. The anterior end of the ramus below the incisors and It should be indicated, canine has a somewhat different appearance in Preptoceras than in present in molar teeth Ovibos, being fuller dorsoventrally and of greater depth. The condyle no. 1009 the style is cle; slopes downward more toward the inner side than in the musk ox. but in the type, no. 8896 The coronoid process considerably overhangs the condyle. The inner face of M!, which anterior margin of the process is broadly convex in its extent from Ovibos a similar style 1 the anterior border of the ascending ramus to the upper end. noted by Riitimeyer, b~ Ovibos in the Universi· MEASUREMENTS OF SKULL, No. 27118 function and worn, the Greatest transverse width of occiput above occipital condyles ...... 148. mm. molars. In no. 27118 ~ Greatest transverse width o.f condyles ac1oss posterior articulating present. surface ...... 88.3 In p! no style is pi Greatest transverse diameter of foramen magnum, measured between tooth as in the musk ox. inner borders of occipital condyles ...... 37.1 Greatest dorsoventral diameter of foramen magnum ...... 23.8 tudinal groove assists i Height of occiput measured from ventral surface of occipital condyles pillar (pl. 62, fig. 2). to superior border ...... 107.3 surface occur two depr Width of cranium measured between outer surface of lateral walls of parietals ...... 108. the deeper one. A soi Greatest width measured between lower borders of horn cores ...... 150.2 seen in P~ and P! but · Least distance between basal margins of horn cores ...... 36.4 than in P!. Well deve Least distance across frontals measured between the orbital rims and the basal margins of the horn cores ...... 134.9 on the outer sides of th, Greatest width across frontals and between posterior rims of orbits 192.3 A small enamel-enc Greatest diameter (dorsoventraU) of horn core near base ...... 96.8 worn molar teeth lyin~ Transverse (anteroposteriorf) diameter of horn core near base ...... 76.7 Length of diastema between P;; and alveolus for canine...... __ 73.3 The lower incisor a Length of symphysis ...... 48.6 and have not been fou Depth of ramus at anterior end of P;; measured normal to inferior in the McKittrick spec border ---·--··-·------···------·--·-----·--·--··------··------·------·------·------38 to the Depth of ramus at posterior end of Ma measured normal to inferior Preptoceras-Euc border ···------·------··-·------·--·------··--·------··-·--·---·--·--·--·--··-·------· ·----- a 61.8 teeth were larger than Greatest transverse diameter of ramus at M:; ...... 26 the incisors are very Height of condyle above inferior border------...... 136.6 than in other ruminalll Height from inferior border to tip of coronoid process ...... a 174. Length from anterior end of symphysis to posterior border of ascend- 4 Osgood, W. H., Smit! ing ram us ...... 336.5 5 Lonn berg, E., On t Length from anterior end of symphysis to posterior border of condyle 357 moschatus), Proc. Zool. S a, approximate. , Geological Sciences [Vol.16 1927] Stock-Furlong: Preptoceras-Euceratheritum from McKittrick 419 e of no. 27118 is smaller Dentition.-In no. 27118 the lower premolar series (P2 to P 4 iheek-tooth series relatively inclusive) is longer relative to the lower molar series than in Ovi"bos. i extension of the ramus This proportionately greater length of the premolar series is not is occasioned by a greater evident when the superior dentition is compared .with that of Ovibos. ~ former genus. The ramus The superior dental series resembles that in Preptoceras and Eucera exposed posterior portion therium from Samwel Cave. Furlong noted in Preptoceras the pres ~bos. The posterior dental ence of a very small accessory style formed in the re-entrant angle mental foramen is smaller between the anterior and posterior crescents of the inner wall of the ng anterior to it, as in the superior molars and stated that the style is absent in Euceratherium. nus below the incisors and It should be indicated, however, that the style is not invariably tee in Preptoceras than in present in molar teeth of Preptoceras from the cave deposits. In ~reater depth. The condyle no. 1009 the style is clearly in evidence, particularly in M! and Mg,, side than in the musk ox. but in the type, no. 8896, the style is not to be seen along the exposed hangs the condyle. The inner face of Mg,, which extends some 11 mm. below the palate. In convex in its extent from Ovibos a similar style may be present in the upper molar teeth as .s to the upper end. noted by Riitimeyer, by Lonnberg, and by Osgood.4 In a skull of Ovibos in the University collections in which all the teeth are in ~o. 27118 function and worn, the accessory column is not present in the upper 1ital condyles.------ 148. mm. molars. In no. 27118 from McKittrick no median accessory style is sterior articulating present. 88.3 In pa no style is present along the anteroexternal border of the ,, measured between 37.1 tooth as in the musk ox. On the outer surface a well developed longi rnm ______23.8 tudinal groove assists in the definition of the anterior and posterior if occipital condyles pillar (pl. 62, fig. 2). Along the posterior border of the wearing 107.3 ce of lateral walls surface occur two depressions of which the inner is the smaller and 108. the deeper one. A somewhat similar pattern of wearing surface is of horn cores ______150.2 seen in P! and P .! but the crests of the crown are more fully formed ores------36.4 m the orbital rims than in pa. Well developed anterior and posterior styles are present 134.9 on the outer sides of these teeth. .erior rims of orbits 192.3 A small enamel-enclosed pit is seen on the wearing surface of the 96.8 near base ------ worn molar teeth lying between the two enamel lobes. core near base ------76.7 : canine ______73.3 The lower incisor and canine teeth have dropped from the alveoli 48.6 and have not been found in the collection. Judging from the alveoli normal to inferior in the McKittrick specimen and from mandibular materials belonging 38 I normal to inferior to the Preptoceras-Euceratherium group of the California caves, these a 61.8 teeth were larger than in Ovibos. Lonnberg5 has stated that in Ovi"bos 26 the incisors are very small, comparatively thick, and less spatulate 136.6 1rocess ------a 174. than in other ruminants. In the Pleistocene forms from California the or border of ascend- 4 Osgood, W. H., Smithsonian Misc. Coll., vol. 48, p. 177, 1905. 336.5 5 Lonnberg, E., On the structure and anatomy of the Musk-ox (Ovibos or border of condyle 357 moschatus), Proc. Zool. Soc. London, p. 709, 1900. 420 Unwersity of California Publications in Geological Sciences LVol. 16 1927] Stock-Furlong: Prej lower incisors and canine resemble much more closely the comparable Pes.-Elements of th1 teeth in the musk ox than they do those in Ovis or in Oreamnos. the astragalus, cubo-na.vi< In the lower premolar series t!J.e teeth become progressively more phalanges, no. 27119. Tht molariform from P 2 to P 4 inclusive (pl. 63, fig. la)). In the second are shown in :figures 3 a1 premolar two crests extend backward and inward from the principal cusp. The posterior of the two crests forms the outer and posterior rim of the occlusal surface. In P3 the principal outer crest, which extends forward, bifurcates anteriorly, the two crests continuing to the inner side. A transverse crest connects the principal outer crest with a median pillar of the inner side. A posterior lobe, completely enclosed by enamel on the occlusal surface, is defined anteriorly on the external surface of the a tooth by a distinct longitudinal furrow. The groove is more pro nounced than in Ovibos. P4 resembles that in the musk ox. In this tooth the posterior moiety is less compressed anteroposteriorly than in P3 and is more strongly suggestive of the posterior half of M1. In M3 the third or posterior lobe does not reach the stage of development Fig. 3. Preptoceras? cf. seen in the comparable tooth of Ovioos. Mus. Pal. Vert. Coll., X 0.5( d, view of surface articulatin MEASUREMENT OF DENTITION, No. 27118 fornia. Greatest length of cheek tooth series, P! to M! inclusive------······-······-- 136.9mm. P!, anteroposterior diameter -·····-···--···-········-····-··········-····-·--····················· 14.6 P!, transverse diameter --·········-·-··--··--···-·--·-···--··-········-····--·····-····--·-···-·····-·· 13.8 A·at: - P!, anteroposterior diameter at wearing surface ····-·········-·-··-················ 17 P!, transverse diameter -····---····-···--··········-----········---····-···-··----····-·····-········· 14 P!, anteroposterior diameter -···········-·····-···-·-····-···-········---··············---····-··· 18 P!, transverse diameter ···-··--····-···-··········-···························-···---·--···-·····-·····- 14 Ml, anteroposterior diameter ····-········-··--····--·--···································· ······ 26.9 Ml, transverse diameter ····-····-···-····-···--··-········i--····-·······--········-······-······--·· 19.2 M!, anteroposterior diameter ····-·······-·······-·-·······----··--······-························· 30.2 M!, transverse diameter ·--·-······-················-----··········-··-··········-················· ····· 17.2 M!, anteroposterior diameter ·············-··--·················-··-·························-· ···· 29.1 M!, transverse diameter ···-·····-···············-·····-·······-·--·····-···············-·-············· 16.1 Length of cheek-tooth series from anterior end of P 2 to posterior end of M;; --··-·--······-··--·-······-··-··--·······-··········-··--····--···········-·-········-······-·-···-·--··· 146.7 P2, greatest anteroposterior diameter ·····----·······--····-····-·····-··-·--··········--··· 13.5 Fig. 4. Preptoceras? cf U. C. Mus. Pal. Vert. Coll, P;;, greatest transverse diameter -···-·····-········-···················--·····-·······--·----·· 9.2 for calcaneum, Ca, and for P0, greatest anteroposterior diameter ······-····----·········-·······-···--····-·-········· 17.5 for metopodial, Mt, for fus P;;, greatest transverse diameter ··········-·············-··················-··--·····-·········· 11.1 cuneiform, Enc; c, anterioi P;, greatest anteroposterior diameter ·····-·····-····-·····-······-··········-··········--·· 20.6 fornia. P;, greatest transverse diameter ·············-···············-·-··-···-·····-····-···········--· 13.3 M;:, greatest anteroposterior diameter ····-·················---···---·····-················· 25.9 and shape the comparal M;:, greatest transverse diameter -··-·--···---··---···-·········-·····--··········-·--·---····: 13.1 ceras-Euceratherium g1 M;;, greatest anteroposterior diameter ·-····--····················-···--··············--··· 30. Mz, greatest transverse diameter ······-····---····-·----···-·········--···--···········--··· .. 13. The cannon bone ( M3, greatest anteroposterior diameter -·········-····-···--·······-···-:...... 38.2 closely in general appe M0, greatest transverse diameter ·-··-················-········-·--···························· 13.2 Geological Sciences l Vol. 16 1927] Stoc7c-Furlong: Preptoceras-Euceratherium from McKittrick 421 ire closely the comparable Pes.-Elements of the feet available from McKittrick include Ovis or in Oreamnos. the astragalus, cubo-navicular, the two posterior cannon bones and ecome progressively more phalanges, no. 27119. The astragalus and fused cuboid and navicular fig. la) ) . In the second are shown in figures 3 and 4. The tarsal elements resemble in size nward from the principal ts the outer and posterior (tends forward, bifurcates inner side. A transverse th a median pillar of the nclosed by enamel on the ie external surface of the a b c The groove is more pro Gin the musk ox. In this :ed anteroposteriorly than d ~ posterior half of M1. In i the stage of ·development Fig. 3. Preptoceras? cf. sinclairi Furlong. Right astragalus, no. 27119 U. C. Mus. Pal. Vert. Coll., X 0.50. a, anterior view; b, posterior view; o, outer view; d, view of surface articulating with cubo-navicular. McKittrick Pleistocene, Cali No. 27118 fornia. ilusive ...... 136.9 mm. 14.6 13.8 17 14 18 14 26.9 19.2 30.2 17.2 29. 1 16.1 P; to posterior end c 146.7 13.5 Fig. 4. Preptoceras? cf. sinclairi Furlong. Right cubo-navicular, no. 27119 9.2 U. C. Mus. Pal. Vert. Coll, X 0.50. a, proximal view with articulating surfaces for calcaneum, Ca, and for astragalus, As; b, distal view with articulating facets 17.5 for metopodial, Mt, for fused ecto- and mesocuneiform, Ee and Mc, and for ento 11.1 cuneiform, Enc; c, anterior view; d, outer view. McKittrick Pleistocene, Cali 20.6 fornia. 13.3 25.9 and shape the comparable bones belonging to members of the Prepto 13.1 30. ceras-Euceratherium group from the Pleistocene of the Shasta caves. 13. The cannon bone (fig. 5a, b, c) is slightly smaller but resembles 38.2 closely in general appearance no. 8556 from the Pleistocene of Potter 13.2 422 University of California Publications in Geological Sciences [Vol.16 1927] Stock-Furlong: Pr Creek Cave determined by Sinclair6 as belonging to the genus Eucera slenderness the McKittri therium. The McKittrick specimen is more slender. A second cannon cannon bones from Pot bone from Potter Creek Cave, no. 8152, approaches m<>re closely in its metatarsal V is best dev well represented in no. ~ No. 27119 resembles c Er.+l'vfc Preptoceras, no. 9361 fro resemblance between th between the McKittrick In Ovis the cann<>n l much more slender. Thi sion seen in the McKittI on the cannon bone of a end <>f the cannon bone ing surface for the cub facet in no. 27119 is re] As might be readily phalanges are all mucl the proximal phalanx i: in the manus, and a McKittrick form. In pl farther back along the In the distal phalanx t c<>nvex as in Ovis. Th• have the 'roman nose' is also straighter than · are similar to those in Although the cann fourth smaller than t1 resemblance in shape exists between no. 271 phalanges as well. Ir! widened transversely, : so noticeably in width ately bel<>w the proxh rudiment <>f metatars~ Fig. 5. Preptoceras? cf. sinclairi Furlong. Left cannon bone and phalanges, outer posterior b<>rde1 no. 27119 U. C. Mus. Pal. Vert. Coll., X 0.50. a, inner view; b, posterior view disparity in size betv with view of proximal end (Cu, facets for cuboid; Ee and Mc, facets for fused ecto· and mesocuneiform; Enc, facet for entocuneiform) and cross-section of shaft, cuneiforms and the cu Mt. 5, rudiment of metatarsal V; c, anterior view. In the latter no deep . 6 Sinclair, W. J., New mammalia from the Quaternary caves of California, end between these t'i Univ. Calif. Puhl. Bull. Dept. Geol., vol. 41 pp. 150-152, pl. 20, fig. 1, 1905. i Geological Sciences [Vol. 16 1927] Stock-Furlong: Preptoceras-Euceratheritum from McKittrick 423 mging to the genus Eucera slenderness the McKittrick specimen. In a series of three posterior l slender. A second cannon cannon bones from Potter Creek Cave the proximal rudiment of proaches more closely in its metatarsal V is best developed in nos. 8549 and 8556 and is not so well represented in no. 8152. No. 27119 resembles closely a comparable cannon bone, possibly of - Er+lvfc Preptoceras, no. 9361 from Samwel Cave_ There is probably a greater resemblance between the two elements in slenderness than exists ::nc between the McKittrick specimen and those from Potter Creek Cave. In Ovis the cannon bone is actually longer than in no. 27119 and much more slender. This element does not show the transverse expan sion seen in the McKittrick specimen. In Ovis there is no indication .. ~ , ·::. on the cannon bone of a rudiment or metatarsal V. At the proximal end of the cannon bone in the mountain sheep, the anterior articulat ing surface for the cuboid is relatively large, while the comparable facet in no. 27119 is relatively small. As might be readily inferred from the size of the cannon bone, the phalanges are all much stouter than in Ovis. In the latter genus the proximal phalanx in the pes is distinctly more slender than that in the manus, and apparently more noticeably so than in the McKittrick form. In phalanx II the distal articulating surface extends farther back along the top of the phalanx in no. 27119 than in Ovis. In the distal phalanx the superior border is practically straight, not convex as in Ovis. The phalanx when viewed from the side does not have the 'roman nose' appearance seen in Ovis. The inferior border is also straighter than in the phalanx of Ovis. The ungual foramina are similar to those in the terminal phalanx of the mountain sheep. Although the cannon bone of Oreamnos is approximately one fourth smaller than that of the Pleistocene form, there is greater resemblance in shape of metatarsus between these two genera than exists between no. 27119 and Ovis. This applies in general to the phalanges as well. In the McKittrick specimen the cannon bone is widened transversely, as in ·Oreamnos, but the shaft does not increase so noticeably in width in its downward extent from a point immedi ately below the proximal end, as in the Recent mountan goat. No rudiment of metatarsal V is present along the upper portion of the Left cannon bone and phalanges, outer posterior border of the shaft in Oreamnos. There is greater a, inner view; b, posterior view disparity in size between the facets for the fused ecto- and meso ·id; Ee and Mc, facets for fused liform) and cross-section of shaft, cuneiforms and the cuboid in the Pleistocene form than in Oreamnos. ~w. In the latter no deep pit is to be noted in the middle of the proximal Quaternary caves of California, end between these two facets. Such a pit is well formed in the 150-152, pl. 20, fig. 1, 1905. 424 University of California Publications in Geological Sciences [Vol.16 1927] Stock-Furlong: Prep· McKittrick specimen . . The phalanges of the pes in no. 27119 resemble those of Oreamnos in their heaviness. RESUME OF CHA: In phalanx III of the McKittrick form the plane of the inferior CHARACTERS LIKE THOSE IN surface meets the plane of the outer surface to form an acute angle curvature of horn core; exteni while in Oreamnos these two planes meet in a right angle. Oreamnos ward from base before curvin lower borders of horn cores; i agrees with no. 27119 in lacking the 'roman nose' appearance of the notch; absence of median ridg ungual phalanx when viewed from the outer side. appearance of occiput; parieta CHARACTERS LIKE 'I'ROSE IN horn cores; some resemblance MEASUREMENTS OF ELEMENTS OF PES, No. 27119 of accessory style in upper me Astragalus: CHARACTERS COMMON TO PR: Greatest length ...... 57.9mm. between orbital rims; presen( ~ Greatest width across outer surface ······················-··············- ·········· 31.9 and position of foramina in Transverse width of distal trochlea ·························· ····· ····· ··············- 40.1 occipital condyle; number an( Cubo-navicular: CHARACTERS DISTINGU1SHIN Greatest transverse width ········································--····················-···· 49.7 AND EUCER.A.THERIUM. Width Anteroposterior diameter ······················ - ················································ 44.3 cores; elevation of frontals Left posterior cannon bone: cores; depth of lachrymal d( Greatest length over all ...... 189. border of alisphenoid; angle Length measured on anterior surface ································- ············-·· 182.4 surface of the cranial roof w Width of proximal end ...... 44. 7 Greatest anteroposterior diameter of proximal end······················- 41.8 Width of shaft at middle ··········- ·························· ································ 28.3 Anteroposterior diameter of shaft at middle ...... 24.6 Greatest width across distal condyles ...... 54.8 RELATIONS] Greatest anteroposterior diameter of distal condyles ...... 32.7 E Inner digit: The type specimens o Phalanx I (proximal phalanx): Greatest length ...... 60.2 described from the Pleistc Greatest width of proximal end...... 26.9 California, but the form{ Greatest depth of p1·oximal end ...... 29.3 of Potter Creek Cave, Sh: Greatest width of distal end...... 26.2 Greatest depth of distal end...... 20.2 of Euceratherium, Sincl Phalanx II (middle phalanx): position of this genus to Length from base of proximal articulating surface to middle but stated that the Pleist of distal articulating surface ...... 41.3 North American represe1 Greatest width of proximal end...... 25.9 Greatest depth of proximal end ...... 25.5 Euceratherium and Ovit Greatest width of proximal condyle ...... 20.3 larity in dentition and 1 Greatest depth of proximal condyle ...... 24.8 forms. The genus was Phalanx III (distal phalanx) : because of decided dii'f( Greatest length along base ...... 56.3 Greatest depth ·················································································-· 31.7 therium was also regard Greatest width of proximal end·················································· ·· - 19.5 1 Several teeth referred found in the Pleistocene fa1 Geol., vol. 10, pp. 513-514, s Sinclair, W. J., and Fu Quaternary caves of Califor1 1904. • Geological Sciences [Vol. 16 1927] Stock-Furlong: Preptoceras-Euceratherium from McKittrick 425 e pes in no. 27119 resemble RESUME OF CHARACTERS OF McKITTRICK FORM l the plane of the inferior CHARACTERS LIKE THOSE IN PR.1'.'J>TOCERA.S. Size and shape and presumably .ce to form an acute angle curvature of horn core; extent to which horn core extends outwa rd and back i a right angle. Oreamnos ward from base before curving forward; width across frontals between outer m nose' appearance of the lower borders of horn cores; indentation of palatine on each side of posterior notch; absence of median ridge on occiput above foramen magnum and general ~r side. appearance of occiput; parietals form dorsoposterior roof of skull. CHARACTERS LIKE ~I'HOSE IN EUCER.A.THERIUM. Backward and upward extent of horn cores; some resemblance possibly in curvature; width of palate; absence PEs, No. 27119 of accessory style in upper molars. 57.9mm. CHARACTERS COMMON TO PR.EPTOCERAS AND EUCERATHERIUM. Width of frontals 31.9 between orbital rims; presence of a lachrymal depression; shape of elements 40.1 and position of foramina in basicranial region of skull; position and size of occipital condyle; number and structure of teeth; structure of feet. CHARACTERS DISTINGIDSHING THE McKlTTRJCK FORM FROM BOTH PR.EPTOCER.AS 49.7 AND EucER.ATHERIUM. Width measured between inner basal borders of horn 44.3 cores; elevation of frontals in their extent from fronto-nasal suture to horn cores; depth of lachrymal depl'ession; abrupt downward descent of posterior 189. border of alisphenoid; angle (139°) in vertical plane made by plane of dorsal 182.4 surface of the cranial roof with the plane of the occiput. 44.7 1 end ...... 41.8 28.3 24.6 54.8 RELATIONSHIP OF PREPTOCERAS AND ndyles ...... 32.7 EUCERATHERIUM The type specimens of Euceratherium and Preptoceras were both 60.2 described from the Pleistocene deposit of Samwel Cave, Shasta County, 26.9 California, but the former genus has been recorded also in the fauna 29.3 7 In 26.2 of Potter Creek Cave, Shasta County. a discussion of the affinities 20.2 of Euceratherium, Sinclair and Furlong8 regarded tentatively the position of this genus to be in the ovine division of the bovid group, : surface t o middle but stated that the Pleistocene form is not nearly related to any living 41.3 25.9 North American representa.tive of that division. In the comparison of 25.5 Euceratherium and Ovibos Sinclair and Furlong recognized the simi 20.3 larity in dentition and the decided difference in horn cores of these 24.8 forms. The genus was excluded from a relationship to the cattle 56.3 because of decided differences presented in the dentition. Eucera 31.7 therium was also regarded as not closely related to the existing goats. 19.5 1 Several teeth referred tentatively to Euceratheri'IMfl, collinum have been found in the Pleistocene fauna of Hawver Cave. Univ. Calif. Puhl. Bull. Dept. Geol., vol. 10, pp. 513-514, 1918. s Sinclair, W. J., and Furlong, E. L., Euceratherium, a new ungulate from the Quaternary caves of California, Univ. Calif. Publ. Bull. Dept. Geol., vol. 3, p. 416, 1904. Stock-Furlong: Prep 426 University of California Publications in Geological Sciences [Vol.16 1927] of horn cores, but perhaps 1 In a later paper Sinclair9 described and figured foot material from the Pleistocene of Potter Creek Cave, referring the specimens to to the Ovibovinae. Notice Euceratherium because of an association in the deposit with teeth and cranial region of the sku horn cores determined as belonging to the latter genus. Sinclair therium group is related t< decided from a comparison of the foot materials that Euceratherium best be determined when is not closely related to the existing goat-antelopes or to the sheep. Pliocene precursors of the Sinclair also recognized that the feet differed only in minor details A study of the materi from those of Ovibos. nition of a number of cha1 Furlong,1° although recognizing the resemblance in the dentition, E1weratherium. Thus ma regarded the genus Preptoceras as not nearly. related to Ovi"bos, and cranial region of the skull tentatively placed the form in the Ovinae. Preptoceras was con the characters given in the sidered by Furlong as a type having many characters in common with from both Preptoceras ai only minor significance. Euceratherium, and the suggestion was made that the two forms on further study would be placed in a distinct group. lachrymal is depressed mi a particular group. The In considering Ovibos and allied Pleistocene types occurring out border of the alisphenoid side the California area, several authors have expressed opinions while the preservation of · regarding the relationships of Euceratherium and of Preptoceras. not be complete in the ca\ Thus Gidley11 regards Liops zuniensis as apparently much more closely the inner basal borders oi related to Ovibos than is either Eiteeratheriitm or Preptoceras. Gidley frontal anterior to these s refers Liops to the Ovibovinae. Allen12 does not regard the California a position between that of forms as nearly related to either Symbos or Ovibos. Hay, 13 on the It appears evident frc other hand, refers Euceratherium and Preptoceras to the Ovibovinae, in common by the McKit in which subfamily are placed with Ovibos the genera Symbos and are of greater significanc1 Bootherium. Other authors have also referred Euceratherium and Preptoceras to the Ovibovinae. with either Preptoceras o ships and in view of pos: A comparison of individuals of the Prept.oceras-Euceratherium group with the existing genera, Ovibos, Ovis, and Ore(J!tnnos indicates cores, the suggestion may the types from the Cal' a resemblance in dentition between these forms. Undoubtedly the generic group. Should t greatest similarity exists between the California Pleistocene types and ceras would possibly bt Ovibos. In the elements of the feet, particularly in the cannon bones, Euceratherium to an old1 the former group shows greatest resemblance to the musk oxen, less ceras and Euceratherium resemblance to the goats, and least resemblance to the mountain sheep. precedence over P.reptoc1 The Pleistocene forms differ of course widely from Ovibos in character 9 Sinclair, W. J., Univ. Calif. Publ. Bull. Dept. Geol., vol. 4, pp. 150-152, pl. 20, figs. 1 and 21 1905. 10 Furlong, E. L., Preptoceras, a new ungulate from the Samwel Cave, Cali fornia, Univ. Calif. Publ. Bull. Dept. Geol., vol. 4, pp. 163-169, pis. 24 and 25, 1905. 11 Gidley, J. W., A new ruminant from the Pleistocene of New Mexico, Proc. U. S. Nat. Mus., vol. 30, pp. 165-167, 1906. 12 Allen, J. A., Mem. Am. Mus., vol. 1, p. 1691 1913. 13 Hay, 0. P., The Pleistocene mammals of Iowa, Iowa Geol. Surv., vol. 23, pp. 290-291, 1914. Geological Sciences [Vol. 16 1927] Stock-Furlong: Preptoceras-Euceratherium from McKittrick 427 figured foot material from of horn cores, but per~aps no more widely than do other types referred !ferring the specimens to to the Ovibovinae. Noticeable differences are presented in the basi the deposit with teeth and cranial region of the skull. How closely the Preptoceras-Eucera b.e latter genus. Sinclair therium group is related to the Pleistocene and Recent musk oxen can Gerials that Euceratherium best be determined when information is available concerning the antelopes or to the sheep. Pliocene precursors of these forms. ~red only in minor details A study of the materials from McKittrick has led to the recog nition of a number of characters held in common by Preptoceras and emblance in the dentition, Euceratherium. Thus may be mentioned the characters in the basi rly. related to Ovibos, and cranial region of the skull, in the dentition, and in the feet. Among te. Preptoceras was con the characters given in the resume distinguishing the McKittrick form characters in common with from both Preptoceras and Euceratherium, some appear to possess ide that the two forms on only minor significance. Thus the depth to which the surface of the group. lachrymal is depressed may be regarded as a variable feature within ocene types occurring out- a particular group. The abrupt downward descent of the posterior border of the alisphenoid may be peculiar to the McKittrick skull have expressed opinions ' rium and of Preptoceras. while the preservation of the posterior portion of the alisphenoid may parently much more closely not be complete in the cave skulls. In measurement of width between um or Preptoceras. Gidley the inner basal borders of the horn cores, and in the elevation of the s not regard the California frontal anterior to these structures, the McKittrick specimen occupies or Ovibos. Hay,1 3 on the a position between that of Preptoceras and the type of Euceratherium. 'Jtoceras to the Ovibovinae, It appears evident from the_ comparisons that the characters held ~s the genera Symbos and in common by the McKittrick form, Preptoceras and Euceratherium '.erred Euceratherium and are of greater significance than those which ally the McKittrick type with either Preptoceras or Euceratheri1im. In view of these relation r:'reptoceras-Euceratherium ships and in view of possible variation in· the characters of the horn is, and Orea;mnos indicates cores, the suggestion may be warranted that the McKittrick form and forms. Undoubtedly the the types from the California caves represent in reality a single >rnia Pleistocene types and generic group. Should this prove to be the case the type of Prepto ilarly in the cannon bones, ceras would possibly belong to a young male and the type of 1ce to the musk oxen, less Euceratherium to an older female. If the gene~ic identity of Prepto .nee to the mountain sheep. ceras and Euceratherium be established, the name Euceratheri11m has y from Ovibos in character precedence over P.reptoceras. pt. Geol., vol. 4, pp. 150-152, from the Samwel Cave, Cali- 4, pp. 163-169, pis. 24 and 25, istocene of New Mexico, Proc. 1913. 1wa, Iowa Geol. Surv., vol. 23, UNIV. CALIF. PUBL. BULL. D I EXPLANATION OF PLATE 60 Preptoceras? cf. sinclairi Furlong Skull, no. 27118 U. C. Mus. Pal. Vert. Coll.; dorsal view. X 0.333. McKittrick Pleistocene, California. [428] UNIV. CALIF. PUBL. BULL. DEPT. GEOL. SCI. (STOCK-FURLONG ] VOL. 16. PL. 60 :..ATE 60 Furlong dorsal view. X 0.333. EXPLANATION OF PLATE 61 Preptoceras? cf. sinclairi Furlong Skull, no. 27118 U. C. Mus. Pal. Vert. Coll.; view of right side. X 0.333. McKittrick Pleistocene, California. [430] i' lo c z < () )> r :i 1l c ID r m c r r 0 1l "'-! ~TE 61 Gl 0 Furlong r"' (J) iew of right side. X 0.333. () (J) -! 0 () "''rt c ;u r 0 z Gl < 0 r -Cl 1lr- ~ UNIV. CALIF. PUBL. BULL. DEPT. EXPLANATION OF PLATE 62 Preptoceras? cf. sinclairi Furlong Figs. 1 and 2. Skull, no. 27118, U. C. Mus. Pal. Vert. Coll.; fig. 1, posterior view, X 0.333; fig. 2, palate and right cheek-tooth series, X 0.50. McKittrick Pleistocene, California. Fig. 3. Recent musk ox (Ovibos), palate and cheek-tooth series. X 0.50. [432] UNIV. CALIF. PUBL. BULL. DEPT. GEOL. SCI. [STOCK-FURLONG] VOL. 16. PL. 62 lTE 62 rurlong al. Vert. Coll.; fig. 1, posterior ~h series, X 0.50. McKittrick d cheek-tooth series. X 0.50. 3 EXPLANATION OF PLATE 63 Preptoceras? cf. sinclairi Furlong Fig. 1 and la. Right ramus of mandible, no. 27118 U. C. Mus. Pal. Vert. Coll. X 0.50. Fig. 1, outer view; :fig. la, superior view, horizontal ramus, and dentition. McKittrick Pleistocene, California. Fig. 2. Recent musk ox (Ovibos), superior view of horizontal ramus, and dentition. [434] c z < () )> r :" "ti c CD : CD c r : 0 l'1 "ti :-i Gl l'1 0 : TE 63 (f) () 'urlong 27118 U. C. Mus. Pal. Vert. r view, horizontal ramus, and iew of horizontal ramus, and (f) -I 0 () ::" :" c ;Q r 0 z Gl < 0 :