SIWALIK AND NARBADA EQUIDiE. 
27—93 
of horses "by means of the molar series alone, and there is consequently a certain 
possible element of doubt in the following determinations. 
Upper molars . — In figure 3 of plate XV of this memoir are represented the 
earlier molar teeth of a true horse from the Narbada bone-beds, collected several 
years ago by Mr. Hacket of the Geological Survey. These teeth are implanted in 
a fragment of the left maxilla. At the anterior end of the series is seen the 
broken base of the first premolar, or persistent milk-molar (pm. 1), followed by the 
remaining three premolars (pm. 2 to pm. 4), while the last complete tooth is the 
first true molar (m. 1). The anterior teeth are determined to be premolars from the 
fact of the last of them (pm. 4), being less worn than the succeeding tooth 
(m. 1). 
A comparison of these teeth with the upper molars of E. namadicus repre- 
sented in plate LXXXII, figure 7 of the “ Eauna Antiqua Sivalensis,” will leave 
little doubt but that the two belong to the same species. They differ from the 
corresponding teeth of E. sivalensis by the larger size of the anterior ‘ pillar ’ in the 
last premolar. 
Siwalik specimens. — In figure 3 of plate XIV of this memoir there is repre- 
sented the left maxilla of a horse, collected by Mr. Theobald in the topmost 
Siwaliks of the Hushiarpur district of the Punjab, exhibiting all the teeth of the 
molar series with the exception of the first premolar, or milk-molar (pm. 1), of 
which only the broken base remains. These teeth belong to' the permanent series, 
and are in an intermediate condition of wear : an inspection of the figure will 
at once show that they differ very markedly from the molars of E. sivalensis repre- 
sented in figure 2 of the same plate. This difference mainly consists in the greater 
length of the grinding surfaces of the anterior c pillars ’ of the last two premolars 
(pm. 3, pm. 4), which exceeds the length of any of the corresponding surfaces 
in the true molars. All the anterior e pillars ’ are, indeed, very much larger than 
those of the molar series of E. sivalensis. 
The great difference in the form of the anterior 4 pillars 5 of these teeth from 
those of the molars of E. sivalensis figured in the same plate, appears to leave 
little doubt but that they belong to another species. Comparing them with the 
teeth of E. namadicus from the Narbada, noticed above, the two series are seen 
to agree very closely in the great relative size of the anterior * pillar ’ of the last 
premolar, though in the Siwalik specimen the same ‘pillar’ in the penultimate 
premolar (pm. 3) is equally well developed. Both specimens, however, agree in 
the relatively large size of the grinding surfaces of the anterior ‘ pillars,’ especially 
in the premolars, and I think it not impossible that the two may belong to the same 
species. This inference is confirmed by a specimen of the right maxilla of a 
horse represented in figure 4 of plate XY, and collected by Mr. Theobald in the 
Siwaliks of the Punjab, which seems to be intermediate between the two specimens 
above described. 
The specimen of a right maxilla of a horse from the Siwaliks, represented in 
