16 
INDIAN TERTIARY AND POST- TERTIARY VERTEBRATA. 
than in the specimen figured in this volume, and more resembles the specimen 
figured *in the first volume of this series. Prom the comparison of the various 
available specimens of the second upper premolar of the present species, it will he 
apparent that slight variations in the form of the ‘ cingulum ’ of this tooth may 
occur, which cannot he reckoned as of greater importance than mere individual 
characters. 
3rd premolar. — The penultimate premolar, the third tooth from the left in the 
figure, is of considerably larger dimensions than either of the preceding, its trans- 
verse diameter being greater than the longitudinal. In this tooth, as in all the 
succeeding ones, the ‘ anterior collis ’ is stouter than the posterior. The ‘ pass 5 into 
the * median valley 5 is situated at a considerable distance within the mouth of the 
valley, the latter becoming suddenly very deep behind the ‘ pass.’ When worn down, 
this tooth, like the succeeding teeth, would present two ‘ fossettes ’ on the crown 
(formed by the outer part of the ‘ median valley,’ and by the * posterior valley ’), and 
a notch on the inner border (formed by the outer half of the ‘ median valley ’). The 
e cingulum ’ is distinctly crenulated, and occupies the greater portion of three sides 
of the crown ; it is, however, interrupted on the inner surface of the ‘ posterior 
collis.’ There is no distinct c crochet,’ but there is a rudimentary c combing-plate.’ 
The ‘ dorsum ’ of this tooth is nearly flat, but shows a tendency to the development 
of a ‘ buttress ’ at its antero-external angle. This tooth corresponds very closely 
with two specimens of the corresponding tooth drawn in figures 2 and 5 of plate 
VI of the first volume of this work. In the former of those specimens, however, 
the ‘ crochet ’ is more distinctly developed, and the antero-external angle of the 
crown more bevelled of. Mr. Clift’s specimen has been already noticed. 
4th premolar. — The last premolar, the fourth tooth from the left in the 
figure, has much the same general characteristics as the preceding tooth, the main 
points of difference, irrespective of size, being the greater development of the ‘ but- 
tress ’ at the antero-external angle of the crown, and the presence of a distinct 
‘crochet.’ 
1st true molar. — The first true molar, the fifth tooth from the left, is distin- 
guished from either of the two preceding teeth by its antero-posterior diameter being 
greater than the transverse. The antero-external angle of the crown is produced into 
a well-marked ‘ buttress,’ and the ‘ dorsal ’ surface is in consequence considerably 
sinuated. The ‘ anterior collis ’ is of great stoutness, and bears on its anterior surface 
a vertical groove, while on its posterior surface there is a vertical ridge projecting 
into the ‘median valley,’ which may conveniently be termed the ‘ante-crochet.’ 
The ‘ median valley ’ is wide and spacious, and deepens continually from its entrance, 
there being no internal ‘ pass ’, as in the premolars : a large and blunt ‘ crochet ’ 
projects obliquely into the ‘median valley’ from the ‘posterior collis.’ On the 
internal face of the tooth, the ‘ cingulum ’ is interrupted on the two ‘ colies,’ so as to 
form three distinct portions, — an anterior, a median, which makes a tubercle at the 
entrance to the ‘ median valley,’ and a posterior portion. The ‘ posterior valley ’ is 
