144 



UNGULATA 



ORDER VII 



BalucMtherium Cooper (Fig. 190). 



Fig. 190. 



Baluchitherium grangeri Osborn. Upper Oligocene or Lower 



Miocene, Mongolia. A, Skull and lower jaw, lateral aspect. 1/22- 



With skulls and lower jaws of Aceratherium incisivum Kaup (i), 



and Rhinoceros simus Burchell (C) for comparison. (After Osborn.) 



(From a photograph kindly supplied by the American Museum 



of Natural History, New York.) 



Four upper premolars, the first com- 

 paratively small and simple. 

 B. osborni Cooper, the type 

 species, known by the cer- 

 vical vertebrae and limb 

 bones from the Lower Mio- 

 cene of Baluchistan. B. 

 grangeri Osborn, known by a 

 skull 1 "3 metres in length, 

 from the Upper Oligocene or 

 Lower Miocene of Mongolia. 

 Height of highest part of 

 back about 4 metres. 



P ar aceratherium Cooper. 

 Three upper premolars. Skull 

 less swollen over the frontals 

 than in Baluchitherium. 

 Lower incisors sharply conical. 

 P. bugtiense Cooper. Lower 

 Miocene, Baluchistan. 



Indricothermm Borissiak. 

 Turgai, Turkestan. 



/, asiaticum, I. minus Boriss. Lower Miocene, 



Family 3. Bquidae Gray. 



Dentition complete. 



Nasal hones projecting freely, pointed anteriorly, hornless. 

 Dental formxda : —' ' ~^- Incisors chisel-shaped. Informs the oldest geologic- 

 ally, premolars less complex than molars; in later species, molariform. Superior 

 molars consisting of two external cusps as a rule joined into an ectoloph, two internal 

 cones, and usually two conical or ridge-like elongated or crescentic intermediate tubercles. 

 The internal and intermediate cusps as a rule connected by ridges. In the most 

 primitive forms, inferior molars quadrituhercidar ; generally, however, composed of 



^ Antonius, 0., Phylogenet. Zusammenliang zwlschen Hipparion und Equus. Zeitschr. 

 f. indukt. Alostammungs- und Vererbuiigslehre, 1919. — Btcrmeister, H., Die fossileu Pferde 

 der Pampas Formation. Bueuos Aires, 1875. Suppl. 1889. — Cope, E. D., Proc. Amer. Philos. 

 See, 1889, vol. xxvi. — Depiret, Ch., Revision des HjTacotherides europeens. Bull. See. 

 Geol. France, 1901. — Doxiglass, E., Annals Carnegie Mxis., vol. iv., 1908. — Gidley, J. IF., Bull. 

 Amer. Mus. Nat. Hist. New York, 1901, l^QZ.—amnger, W., Bull. Amer. Mus. Nat. Hist. 

 New York, 1906, 1908. — Huxley, T. H., Address delivered at the Anniversary Meeting of the 

 Geological Society. Quart. Journ. Geol. Society, 1870. — Kowalevsky, W., Sur rAnchitherium 

 et sur I'histoire palcontologique des chevaux. Mem. Acad. St-Petersb. , 1873. — Forsyth Major, 

 O., Beitriige zur Geschichte der Pferde, insbesouders Italiens. Abh. Schweiz. Pal. Ges. , vol. iv. , 

 1877; vol. vii., 1880.— J/ars/i, 0. C, Amer. Journ. Sci., 1879, vol. xvii. ; 1892, vol. xli.— 

 Matthew, W. D., Suppl. to Amer. Mus. Journ. New York, 1903. — Matthew, IF. D., and Gidley, 

 J. IF., Bull. Amer. Mus. Nat. Hist. New York, 1906. — Merriam, J. C, Horses of Rancho 

 la Brea ; New Protohippine Horses ; New Ancliitheriine Horses. Univ. California Publ., vol. vii. , 

 1913. New Horses from the Miocene and Pliocene of California. Ibid., vol. ix., 1915.- — Nehring, 

 A., Fossile Pferde aus deutschen Diluvialablagerungen. Berlin, 1884. — Osborn, H. F., Equidae 

 of the Oligocene, Miocene, and Pliocene of North America. Mem. Amer. Mus. Nat. Hist., n.s., 

 vol. ii. New York, 1918. — Reichenau, W. von, Beitr. Kennt. foss. Pferde aus deutsch. Pleistocan. 

 Abhandl. grossh. hessisch. geol. Landesanst., vol. v., 1915. — Scott, W. B., On tlie Osteology of 

 Mesobippus. Journ. of Morph., 1891, vol. iii. — Wortman, J. L., Bull. Amer. Mus. Nat. Hist. 

 New York, 1896. 



