VERTEBEATE FAUNA OP THE LOITP FORJC BEDS. 25 



F'kotohippus medius, Cope, Amer. Naturalist, 1892, 944. 



Protohippus msignis, Leidy, Cope, Bulletin U. S. G. Survey Terrs., 1874,- 

 No. 1, p. 13; Annual Report do., 1873 (1874), p. 523. MenjcU]ypus in- 

 aignis, Leidy, part, Extinct Mammalia Dakota-Nebraska, 1869, p. 296, pi. 

 XVII, fig. 5. Hujus operis, pi. XVIII, fig. 5. 



In the Uncertainty as to the species to w'liich Leidy' s typical specimen 

 of deciduous dentition should be referred, I give this species a name as 

 above. It is probably the animal described by Leidy as the adult at the 

 later reference above cited. It is a smaller species tiian the P. perditus, 

 with simple enamel plates of the lake borders. My collection contains a 

 considerable part of a skeleton with incomplete skull of an old individual 

 with four worn molar teeth from northern Kansas, by Dr. R. H. Hill. 

 The facial portion of the skull is preserved and it presents no anteorbital 

 fossa. I figure (pi. XVIII) three molars in a fragment of a maxillary bone 

 from Cottonwood creek, Oregon, collected by Dr. J. L. Wortman. A 

 single superior molar from Tehuichila, Vera Cruz, agrees with this species,» 



Protohippus parvulus. Marsh, Amer. Jour. Sci. Arts, 1874, p. 251; 

 Equus parvulus Marsh, op. cit., 1868, p. 374, vol. XLVI. 



Isolated teeth from Hitchcock county, Nebraska, F. Hazard; and speci- 

 mens mentioned below, q. v. Probably referable to P. placidus. 



Protohippus fossulatus, Cope, sp. nov. infra. 



Protohippus sejunctus. Cope, Bulletin U. S. Geol. Survey Terrs., 1873 

 (1874) I, p. 15; Annual Report U. S. G. Survey Terrs., 1873 (1874), p. 524; 

 Amer. Naturalist, 1887, p. 1071, fig. 39. 1 Merychippus insignis, Leidy, 

 2dspecimen, Extinct Mamm. Dakota-Nebraska, p. 299, pi. XVII, figs. 8-9. 



Of this species I have the skull with mandible and entire dentition, 

 with considerable part of the skeleton of an individual obtained by my- 

 self in northeast Colorado, with a nearly entire mandible, and fragments 

 of other individuals from the same locality; a nearly complete skull with 

 dentition and a considerable part of the skeleton from Deep river, Mon- 

 tana, collected by J. C. Isaac. This species is about the size of the P. me- 

 dius, and is considerably smaller than the P. mirabilis, to which it is 

 related. 



Protohippus mirabilis, Leidy; Cope, Bull. U. S. G. Survey Terrs., I, 

 1874, p. 15; Leidy Extinct Mamm. Dakota-Nebraska, part, 1869, pp. 

 299, 327, pi. XVII, figs. 10, 11, 12 (exclus. tigs. 8, 9); ^Protohippus su- 

 premus, Leidy, op. cit., p. 828, pi. XXVII, figs. 3, 4. 



The only material which has come under my observation was obtained 

 in Texas, and is described below. As already remarked, one of the speci- 

 mens referred by Leidy to this species and figured (figures 8, 9, plate 

 XVI) by him, represents probably a large and old individual of the P. 

 sejunctus. It was afterwards concluded by him, and so stated in the Re- 

 port U. S. Geol. Survey Terrs., I, 1873, p. 322, to be probably the P. 



