54 
INDIAN TERTIARY AND POST-TERTIARY VERTEBRATA. 
and shows the three last premolars and the first and second true molars. Its dimen- 
sions are as follows as given by Ealconer : — ■ 
Length of fragment 9 - 4 
„ of existing portion of symphysis . 3’1 
„ of five molars 7'0 
Width between 2nd true molars 2"7 
„ „ premolars 2 - 0 
Greatest depth of ramus 3’6 
Thickness of ramus . . 2'0 
Length of second premolar 1'2 
Width of „ „ 0-75 
Length of third 1*2 
Width of „ „ l’O 
Length of fourth 1‘7 
Width of „ | 1-15 
Length of first true molar l - 6 
Width of „ „ 1:3 
Length of second „ 1’9 
Width of „ „ 1-36 
These dimensions show that this mandible must have belonged to a smaller 
individual than the cranium described above : the one may have belonged to a 
female and the other to a male. 
Young mandible . — In figure 5 -of plate NVI of the memoir of Messrs. Baker 
and Durand, already cited, there is engraved the symphysis of the mandible of a 
rhinoceros, which is stated in the text to contain four molars, the last of which is 
unworn ; as there are no earlier teeth, it is presumed that they belong to the milk- 
molar series. These teeth extend nearly up to the present end of the symphysis, 
the tip of which is stated to have been broken away. Unfortunately the posterior 
extremity of the symphysis is not shown in the figure, it being probably not cleared 
from matrix. The extension of the early part of the molar series, far on to the 
symphysis, seems to show that this jaw is of the same type as the one described 
above, and that when complete it was produced into an edentulous spatulate 
extremity. The dimensions of the specimen are not given. 
The last milk-molar in this specimen, as noticed by its describers, is remarkable 
for bearing an isolated pillar in its posterior crescent. In this character it agrees 
with a lower molar of a rhinoceros figured in plate VI, figure 7 of the first volume 
of this work. That specimen belongs to a fragment of the right ramus of the man- 
dible containing a similar but larger tooth. The figured tooth was considered in the 
first volume to be a true molar, but from its agreement with Messrs. Baker and 
Durand’s specimen it would seem to be a milk-molar, as was considered to be the 
case by Dr. Ealconer. The symphysis of this jaw is not shown, but it does not 
seem likely that it could have extended backwards as far as the figured tooth. 
In figure 5 of the same plate of Messrs. Baker and Durand’s memoir, there is 
figured the fragment of the left ramus of a young mandible, stated to contain the 
third and fourth milk-molars, each of which presents a similarly isolated pillar in the 
posterior crescent. This specimen, however, seems to show pretty clearly that these 
