TEETH OE EXTINCT MAMMALIA. 
165 
Fig. 101, 
Ox. 
Ox, common, from shell-marl, Forfar¬ 
shire ; true molar, upper jaw ; two- 
thirds uut. size. Recent. 
c. Grinding surface, d. Side view, 
fangs uppermost. 
Fig. 102. 
a h 
Bear. 
a. Canine tooth or tusk of hear (Ursus 
spelmus ); from cave near Liege. 
1). Molar of left side, upper jaw; 
one-third of nat. size. Post-plio¬ 
cene. 
; Hijcena Goldf. (variety of//. ; 
c. Canine tooth of tiger ; lower jaw. Kent’s Hole, Torquay, Devon- 
recent. d. Outside view of pos- shire; one-third nat. size. Post-pliocene, 
terior molar, lower jaw; one- 
third of nat. size. Recent. 
Teeth of a new species of Arvicola, field-mouse ; from the Norwich Crag. 
Newer pliocene. 
a. Grinding surface, b. Side view of the same. c. Nat. size of a and b. 
On comparing the grinding surfaces of the corresponding 
molars of the three species of elephants. Figs. 93, 94, 95, it 
will be seen that the folds of enamel are most numerous in 
the mammoth, fewer and wider, or more open, in M antiquus; 
and most open and fewest in E. meridionalis. It will be also 
seen that the enamel in the molar of the Rhinoceros ticJio- 
rhinus (Fig. 97), is much thicker than in that of the Rhinoc¬ 
eros leptorhinns (Fig. 96). 
