SIWALIK AND NARBADA EQUIDiE. 
21—87 
structure of its upper milk-molars, and by its generally larger size. The remains of 
this species are at present only known to me from the Siwaliks of the Punjab, and 
from Perim Island : from the latter locality certain upper molars, now in the 
Indian Museum, were catalogued by Dr. Ealconer as belonging to Equus } It is 
not impossible that the extremity of the mandible of an equine animal from Burma 
represented in figure 12 of plate LXXXII of the “ Pauna Antiqua Sivalensis ” 
may belong to the present species, as the Irawadi beds generally yield fossils of an 
old type. It is also possible that the fossil hippotherian teeth from China, referred 
to above, may belong to this species. 
Genus II : EQUUS, Linne. 
Horses in which the feet are normally monodactyle and the anterior ‘ pillar 5 
of the upper molars united throughout its length with the adjacent £ crescent.’ 
By many modem zoologists the old genus Equus is subdivided into Equus, con- 
taining the horse only, and Asinus, containing all the other living members of the 
family; as, however, the distinctions between these two groups rest solely on exter- 
nal characters, they are manifestly inapplicable to any but the living species. 
Species 1. Equus sivalensis, Ealc. and Caut. 
Previous history . — With the exception of the notice of fossil Indian horses by 
the late Sir W. E. Baker already referred to, we have only the plates in the “ Eauna 
Antiqua Sivalensis ” to depend upon for the identification of this species. The 
specific name seems to have first appeared in that work. As it appears to me that 
the remains of two species have been figured in the “Eauna Antiqua Sivalensis” 
under the name of E. sivalensis, it is necessary to determine which specimens are 
to be considered as the type of that species. I have accordingly taken the skull 
represented in figures 1, 1 a, 15 of plate LXXXI of that work as the type, since it is 
the most perfect specimen figured. 
Upper molar series . — An inspection of the figures of the teeth in the above- 
mentioned type skull, or still better, of those of a cast of the same specimen, shows 
that the specimen bears the two last premolars and the three true molars. The 
teeth are very much worn, the first enamel island having totally disappeared in 
the penultimate premolar, and both these islands in the first true molar. The 
grinding surfaces of the molar series are characterised by the small size of the 
anterior ‘ pillar ’ in the premolars, the grinding surface of which is never larger 
than the same surface in the second true molar. 
Another specimen of a much worn upper molar series, drawn in figure 3 of 
plate LXXXII of the same work, exhibits the same general dental characters. 
In figure 2 of plate XIV of this volume is represented the complete left upper 
permanent molar dentition of the skull of a horse, collected by Mr. Theobald in the 
1 See “ Pal. Mem.,” Vol. I, page 188. 
