SIWALIK AND NARBADA EQUIDiE. 
9—75 
the complete isolation of the anterior * pillar ’ : in the much-worn tooth, however, 
this £ pillar ’ is united to the first inner ‘ crescents ’ in Hippotherium, as in JEquus. 1 
The plications of the central folds of enamel in the upper molars are generally 
greater in the former than in the latter genus. 
Genus I. HIPPOTHERIUM, Kaup. 
Hippaeion, Christol. 
This genus may he shortly defined as follows. Tridactyle 3 horses, in which 
the first pillar, in the upper molars, is disconnected from the first inner e crescent ’ 
for at least three-quarters of its length. 
Species 1 . Hippotheeium antilopinum, Ealc. and Caut. 
Syns : Hippaeion antilopinum, Gaudry. Equus peimigenius, von Meyer. 
History. — As stated in the introduction, this species seems to have been first 
named in the “Eauna Antiqua Sivalensis,” and we must, therefore, trust to the 
figures there given, and the measurements in the descriptions of the plates, for its 
identification. In plate LXXXII of that work there are drawn several specimens 
of the dentition, which must he taken as the types of the species. These will he 
referred to as we proceed. 
At a later period, as already noticed in the introduction, H. von Meyer referred 
all the remains of Indian hippotheres then known, to the European Hippotherium 
gracile (Hquus primigenius). We shall subsequently see that there is good 
evidence to show that there are, at least, two Indian species of the genus, hut that 
von Meyer’s conclusion as to the identity of H. antilopinum with H. gracile may 
possibly be correct. 
M. Gaudry’ s conclusion as to the probable monodactyle character of this 
species will be alluded to below and shown to be untenable. 
Upper molar series. — In figure 13 of plate LXXXII of the “ Eauna Antiqua 
Sivalensis,” an upper jaw, with the molar series, of Hippotherium antilopinum is 
figured, and described as belonging to the left side. A cast of this specimen, how- 
ever, in the Indian Museum, shows that the figure has been reversed, and that 
the jaw really belongs to the right side. It contains six teeth, which seem to be 
the three true molars, and the three last premolars. The portion of the bone 
where the persistent milk-molar should be has been broken away, so that that tooth 
1 Vide Gaudry, op. cit., fig. 166. 
This is on the supposition that M. Gaudry ’s conclusions as to the monodactyle character of U. antilopinum 
are incorrect. 
