ELEPHANTS 
713 
head rather than from the withers, owing to the higher car¬ 
riage of the head. Other differences are the presence of a 
nipple on the lower edge of the tip of the trunk as well as 
the one on the upper, the larger tusks, and the lesser number 
of hoof-like nails on the margin of the hoof in the African. 
The genus Loxodonta is a much less specialized group than 
Elephas , as shown by the lesser number of enamel plates 
in the molar teeth and the rounded outline of the dorsal 
surface of the skull. The enormous size of the ears, the 
additional nipple on the tip of the trunk, and the lesser 
number of hoof-like divisions in the feet of Loxodonta are, 
however, specializations not found in the living representa¬ 
tive of the genus Elephas . In skull shape the African is, 
however, decidedly like the genus Mastodon , being evenly 
rounded over the parietal or occipital part, and also convex 
in profile on the forehead above the nasal opening, instead 
of concave as in Elephas . In tooth structure it is somewhat 
intermediate between Mastodon or Stegodon and Elephas , the 
number of plates being intermediate in number and the teeth 
narrower and often showing, when unworn, a want of cement 
on the crown, so that the enamel plates project when unworn 
as ridges similar somewhat to the condition found in Mastodon. 
The teeth, however, are long-crowned, as in Elephas , and very 
different in this character from the short-crowned teeth of 
Mastodon . The Indian elephant, although having as many 
as twenty-four plates to its last molar tooth, is not the most 
highly specialized form in this regard, but such distinction 
belongs to the recently extinct hairy elephant, or mammoth, 
Elephas primigenius , of the boreal regions. The plates in 
the mammoth number as many as twenty-seven in the last 
molar and were narrower, much more crowded, and longer 
than in the Indian. The molar teeth of all elephants have 
progressively more and more ridges as we advance from 
the first to the last tooth in the order of their succession. 
Usually only the formula of the last three, or permanent 
set, is considered. In the African elephant the ridge formula 
in the permanent molars is: first, 6 or 7; second, 8 or 9; 
and last, 10 or 12. In the Indian this formula runs usually: 
first, 12; second, 16; and third, 24. The two living ele¬ 
phants are both less specialized than some of the extinct 
forms belonging to the same genera. In a broader way. 
