6 
MOLAE TEETH AND OTHEE EEMAINS OF MAMMALIA. 
towards the smaller posterior collis (pn the left). The crochet is long, pointed, and 
simple : there is no antecrochet or combing-plate. The posterior valley forms a 
long narrow slit, cutting into the left side of the figure. There is a small infold 
of enamel on the anterior side of the first collis ; there appears to be no cingulum 
on the anterior surface. 
The peculiar straight dorsum occurs, as in the molars ; but this is distinguished 
in the premolars by the absence of any distinct costa, and by the antero-external 
angle being sharper. The dimensions of the premolar are— 
In. 
External side ... ... ... ... ... ... ... 2*5 
Internal side ... ... ... ... ... ... 1'8 
Anterior side ... ... ... ... ... ... ... 2'6 
Posterior side ... ... . ... ... ... ... 2*3 
The molars of this species may be shortly distinguished by the following 
points : — 
“ Narrow median valley ; simple crochet ; straight dorsum ; absence of combing- 
plate, of buttress at external angle, of antecrochet, and of tubercle at entrance 
of median valley ; three fossettes on worn-crown.” 
The persistent dentition of this species seems to be less complete than that 
of any other species of Rhinoceros. In the young skull figured in the “ Fauna 
Antiqua Sivalensis” {plate 1) the last molar has not pierced the gum, and 
only two premolars are present : the first of these is a small, imperfect, triangular 
tooth, and does not seem to have had any tooth in advance of it, which view 
is borne out by the narrowness and smallness of the alveolar border of the maxilla 
in front of this tooth. If still younger specimens are procured, it would be inter- 
esting to make a section of the maxilla to see if there are any rudiments of the 
anterior premolars “ in alveolo.” For the present the persistent dental formula 
must be written as follows : — 
I- 4^- c. ^ P. M. -lEl 
The penultimate upper premolar, as before said, is a small and irregularly 
triangular tooth with a smooth dorsum ; the least premolar is a much larger tooth, 
with a straight dorsum having a single median costa opposite the median valley ; 
the true molars have all two costae on the dorsum. The dimensions of the molars 
in the above-mentioned cranium are as follows : — 
In. 
Length of penultimate premolar ... ... ... ... ... I-IO 
Length of last ditto ... ... ... ... ... 1*65 
Length of first molar ... ... ... ... ... ... 1*90 
Length of second ditto ... ... ... ... ... ... 2*20 
Width of penultimate premolar ... ... ... ... ... 0*89 
Width of last ditto ... ... ... ... ... ... 1*50 
Width of first molar ... ... ... ... ... ... 1*85 
Width of second ditto ... ... ... ... ... ... 1*90 
( 21 ) 
