208 



TITANOTHERES OF ANCIENT WYOMING, DAKOTA, AND NEBRASKA 



Etymology. — giganteum, gigantic; in obvious allu- 

 sion to the great size, which seems to have impressed 

 all the early observers of Titanotherium. 



Present determination. — Leidy himself subsequently 

 (1854.1, p. 157) transferred this species to T. proutii. 

 It is indeterminate. 



Figure 164. — Type (holotype) 



coloradensis. Nasals and 



One-third natural size. 



After Leidy, 1873. A, Top view; B, front view; C, view of left side, 

 Leidyotherium Prout, 1860 

 (Indeterminate) 



Original rejerence. — Acad. Sci. St. Louis Trans., vol. 

 1, pp. 699-700, 1860 (Prout, 1860.1). 



Subsequent rejerence. — Leidy, Extinct Mammalia of 

 Dakota and Nebraska, p. 390, 1869 (Leidy, 1869.1). 



Type species. — None designated. 



Type locality. — The specimen was reported to have 

 been obtained near Abingdon, in Virginia, but was 

 later stated by Leidy (op. cit., p. 390) to be "a fossil 

 from the Mauvaises Terres of White Kiver, Dakota." 



Type. — "The fragment of a large molar tooth." 



Generic characters. — Prout writes: 



The lobed or indented border of the enamel would seem to 

 show that this animal was nearly allied to Titanotherium, while 

 the great width and depth of the groove between the outer and 

 what may have been the inner border of the tooth would sepa- 

 rate it from this genus. * * * It is distinguished, more- 

 over, from these [Lophiodon] by the greater length of the fangs 

 and the comparative shortness of the enamel on 

 the outer surface of the tooth. * * * j^ must 

 have been a phytivorous pachyderm, as large if 

 not larger than the Titanotherium. 



Etymology. — Named in honor of Joseph 

 Leidy. 



Present determination. — No specific name 

 ■;. is given. Leidy treated the genus as syn- 

 onymous with Titanotherium. It is an 

 indeterminate member of the family. 

 Megacerops Leidy, 1870 

 Cf. Megacerops, this monograph, page 541 

 Original reference. — Acad. Nat. Sci. Phila- 

 delphia Proc, vol. 22, p. 2, 1870 (Leidy, 

 1870.1). 



Subsequent reference. — Leidy, Extinct ver- 

 tebrate fauna of the Western Territories, 

 p. 239, pi. 1, figs. 2, 3; pi. 2, fig. 2, 1873 

 (Leidy, 1873.1). 



Type species. — Megacerops coloradensis 

 Leidy. 



Generic characters. — In the original refer- 

 ence a detailed description of the type 

 specimen of Megacerops coloradensis is given, 

 comparisons being made with the anterior 

 horn cores and nasals. of the Siwalik Sivathe- 

 rium, with which it was thought possibly to 

 be allied. Leidy concludes as follows: 



It is probable that the fossil may pertain to the 

 same animal as the remains from the Mauvaises 

 Terres of Nebraska, described under the name of 

 Titanotherium, but in the state of extreme uncer- 

 tainty as to its collocation, it may with equal 

 probability be referred to other genera, perhaps 

 to Megalomeryx, or it may have been an American 

 species of the Sivatherium. Under the circum- 

 stances it may be referred to a new genus, with the 

 name of Megacerops coloradensis. 



Etymology. — jxkya^, great; Kfpas, horn; &4', 

 face. 



Present determination. — Leidy's carefully 

 executed figures of the type, in the opinion 

 of the present writer (Osborn), reveal the 

 generic relationship of this animal with that later de- 

 scribed by Cope (1873.2, p. 4) as Megaceratops acer. 

 Megacerops coloradensis Leidy, 1870 

 Cf. Megacerops coloradensis, this monograph, page 544 

 Original reference. — Acad. Nat. Sci. Philadelphia 

 Proc, vol. 22, p. 2, 1870 (Leidy, 1870.1). 



Subsequent reference. — Leidy, Extinct vertebrate 

 fauna of the Western Territories, pp. 239-242, pi. 1, 

 figs. 2, 3; pi. 2, fig. 2, 1873 (Leidy, 1873.1). 



Type locality and geologic horizon. — Colorado ; Chad- 

 ron formation {Titanotherium zone), level not ascer- 

 tained. 



