SIWAL1K AND NABBADA EQUIDiE. 
29—95 
generally exhibit less plication of their borders, and the first milk-molar, if present, 
is always smaller than in E. namadicus. 
In E. hemionus the grinding surfaces of the anterior ‘ pillars ’ of the upper 
molars are of comparatively small size, and the first milk-molar is always shed at 
an early period. 
In E. onager the anterior ‘pillars’ of the upper molar series present a 
close resemblance to those of E. namadicus, their grinding surfaces being long, 
and that surface in the last premolar being longer than in any other tooth. In the 
recent species, however, the central enamel islands have their borders less plicated 
than in the fossil, and the small first milk-molar disappears at an early age. 
I am unable to make any comparisons between the teeth of- E. namadicus 
and those of the living African Equidce, and I cannot identify them with any of the 
fossil European or American forms. 
Skull. — Erom a cast of the incomplete skull figured in plate LXXXI, figures 
5 and 6, of the “ Eauna Anti qua Sivalensis, ” the only comparison that I can make is 
that the skull belongs to the elongated type of that of the common horse, the 
relative length of the molar series to that of the interval between the last true 
molar and the foramen magnum being 1 to 1'28. This shows that in respect to 
the skull, E. namadicus is more nearly related to the horse than to the wild asses 
of Asia (see above, p. 24). 
Mandible. — In the “ Eauna Antiqua Sivalensis ” (plate LXXXI, fig. V) a lower 
jaw of a fossil horse from the Narbada, referred to E. namadicus, seems to be indistin- 
guishable from that referred to E. sivalensis. This opens up the question whether 
the jaw referred to the latter is correctly determined, and whether it may not really 
belong to E. namadicus ; on the other hand, it is quite likely that E. sivalensis 
may occur in the Narbada. As there seems at present no means of settling this 
question, I have adopted provisionally Ealconer’s determination of the mandible 
of E. sivalensis, and shall merely refer here to another form of mandible from the 
Siwaliks, which may belong to E. namadicus. The teeth of the specimen in 
question are represented in figure 5 of plate XII of this volume ; they comprise 
the three true molars. The specimen consists of a portion of the right ramus of 
the mandible, and was obtained by the late Conductor J. Dawe, from the Siwaliks 
in the neighbourhood of Nahan ; it was referred by Dr. Ealconer to E. sivalensis. 
The elongated teeth and the bold loops of the enamel render it probable that the 
specimen belongs to Equus. The jaw is more slender than the specimen figured in 
the “ Eauna Antiqua Sivalensis ” as the mandible of Equus sivalensis, and yet the 
teeth are of absolutely larger size, indicating the probability of the specific distinct- 
ness of the two specimens. It would be unsafe to make any more precise attempt 
at the specific identification of the present specimen. 
Other remains. — In figures 9, 10, 11 of plate LXXXII of the “ Eauna Anti- 
} See " Pal. Mem.” Vol. I, p. 187 (No. 307)'. 
H 
