TEETH OF EXTINCT MAMMALIA. 
163 
which are among the lowest types of the invertebrata, has 
outlasted that of the mollusca in an equally decided manner. 
Teeth of Post-pliocene Mammalia—To those who have nev¬ 
er studied comparative anatomy, it may seem scarcely cred¬ 
ible that a single bone taken from any part of the skeleton 
may enable a skillful osteologist to distinguish, in many 
cases, the genus, and sometimes the species, of quadrupeds to 
which it belonged. Although few geologists can aspire to 
such knowledge, which must be the result of long practice 
and study, they wdll nevertheless derive great advantage 
from learning, what is comparatively an easy task, to distin¬ 
guish the principal divisions of the mammalia by the forms 
and characters of their teeth. 
The annexed figures represent the teeth of some of the 
more common s.pecies and genera found in alluvial and cav¬ 
ern deposits. 
Fig. 93. 
a b 
' Elephas primigenius (or Mammoth); molar of upper jaw, right side; oue-third of 
uatiiral size. Post-plioceue. 
a. Grinding surface, b. Side view. 
Fig. 94. 
Elephas antiquKSi Falconer, penultimate molar, one-third of natural size. 
Post-pliocene and Pliocene. 
