92—26 INDIAN TERTIARY AND POST-TERTIARY YERTEBRATA. 
Antiqua Sivalensis ” under the name of Equus sivctlensis / but of somewhat larger 
size. It is not impossible that these two types of bones may belong to the two 
species of Siwalik horses, or it is possible they may be merely sexual differences, 
as we have noticed considerable variations in the size of the teeth referred to E. siva- 
lensis. 
The proximal phalangeal bones are much compressed in the middle, and are of 
an elongated type, in both of which respects they resemble the phalangeals of 
Equus hemioniCs, and the zebras, and differ from the corresponding bones in the true 
horses.® All the evidence seems, therefore, to connect E. sivalensis with the asses 
and zebras, rather than with the domestic horse. 
General character of species. — Judging by the remains above enumerated, 
which can certainly be referred to the present species, it would seem that E. siva- 
lensis was most nearly allied to the Tibetan kiang, but that in its retention of a 
‘ larmial \ cavity and of the relatively large persistent first upper milk-molar, and in 
the small size of the grinding surfaces of the anterior c pillars,’ it retained characters 
connecting it with the ancestral genus Rippotherium. If certain remains belong 
to this species, in the inclination of its upper incisors and the form of the symphysis 
of the mandible it more nearly approached the horse ; this is, however, doubtful. 
On the whole, I think it not improbable that this species may have been the 
ancestor of the living kiang of Tibet. 
Distribution. — Remains of £7. sivalensis have been hitherto obtained only 
from the higher beds of the sub-Himalayan Siwaliks to the eastward of the river 
Jhelum. 
Species, 2 Eqtjtjs namadicits, Ealc. and Cant.. 
Synonym E. palseonus, F. and C. 
Ristory. — In plates LXXXI and LXXXII of the “ Eauna Antiqua Sivalensis ” 
are represented certain specimens of the cranium, teeth, and jaws of fossil horses 
under the names of E, namadicus and E. palceonus from the pleistocene deposits of 
the Narbada valley. It has already been stated that these remains in all probability 
belong to the same species, and they will be so considered here. There are no 
means of knowing on what grounds the authors of the above-quoted work distin- 
guished the Narbada from the Siwalik horse, and it is possible that the distinction 
was made merely on the grounds of the different formations whence the speci- 
mens were obtained. In the following descriptions certain molar teeth from 
the Siwaliks will be noticed differing from those we have referred to E. sivalensis , 
and, as far as can be determined with the materials at command, apparently agree- 
ing with the molars of the fossil horse from the Narbada beds. There is, how- 
ever, as already said, always very considerable difficulty in determining the species 
1 Figs. 7, 8. 2 See. De BlainviUe’s “ Osteographie” ‘Equus,’ pi. V. 
