62 
MOLAE TEETH AND OTHER REMAINS OE MAMMALIA. 
on its anterior surface ; this tooth was therefore probably separated by a diastema 
from the preceding tooth, as in Hippopotamus. 
The ultimate premolar has a nearly square base, from which rises a simple 
oblique and compressed cone ; the summit of the cone is directed backwards and 
placed somewhat in advance of the hindmost border of the crown; the anterior 
face of the cone is produced into a sharp sinuous ridge, which extends from the sum- 
mit nearly to the base ; below this the ridge bifurcates and forms a slight- cingulum 
which extends along the greater part of the base of the anterior surface. A small 
tubercle is placed between the summit of the cone and the posterior border of the 
crown ; this tubercle forms the summit of a second cingulum which extends across 
the posterior surface of the tooth ; this posterior cingulum slopes from the central 
tubercle on either side towards the base of the crown ; the outer edge of this cingu- 
lum forms a very distinct ledge at the postero« external angle of the crown ; a 
rounded notch cuts into the outer and the inner sides of the crown, between the 
roots of the fangs the inner surface of the tooth rises nearly vertically from the 
jaw, while the outer surface slopes considerably towards the inner side. The summit 
of the cone is worn obliquely, the facet of .dentine being directed upwards and 
backwards ; the facet of wear presents two planes, the hinder of which is the most 
oblique to the axis of the cone ; the form of the facet is oval, the long diameter 
being placed in the line of the jaw. The enamel of the crown is arranged in 
irregular branching ridges, which radiate from the summit of the cone to the 
periphery of its base ; these ridges are again marked by fine parallel transverse strise. 
The penultimate premolar is somewhat smaller than the last of the series, its 
base approaches a triangular form, constricted laterally between the fangs, and 
blunted at the apex ; the summit of the cone is placed slightly behind the centre 
of the crown, and has a prominent ridge running to the base of the crown, on both 
anterior and posterior surfaces ; there is a well-defined cingulum on the posterior 
surface, which also extends along the hinder half of the internal surface. Like the 
other premolar, the cone is convex and sloping on the external surface, and nearly 
vertical on the internal surface ; this latter surface is divided by a vertical groove. 
The dimensions of this specimen are as follows in inches and tenths : — 
Length, of two molars ... ... ... ... ... 2‘50 
Ditto second molar ... ... ... ... 1‘45 
Width of ditto ditto... ... ... ... ... 1'30 
Height of ditto ditto... ... ..." ... ... 0'80 
Length of ultimate premolar ... ... ... ... 3‘15 
Width of ditto ditto ... ... ... ... 2' 10 
Height of ditto ditto ... ... ... ... 1‘80 
Length of penultimate premolar ... ... ... ... 2'05 
Width of ditto ditto ... ... ... ... 1'80 
Height of ditto ditto .. ... ... ... 1’65 
Depth of jaw at ultimate premolar, . . ... ... ... 3‘10 
Length of the fragment ... ... ... ... 8*00 
( 80 ) 
