558 
UNGULATES. 
There are a larger number of species of mastodon, ranging over a great part 
of Europe, South-Eastern Asia, and the whole of America; the earliest representa¬ 
tives of the group occurring in Europe in the middle division of the Miocene 
period. And it is noteworthy that all these earlier species had but three transverse 
ridges in the third, fourth, and fifth molar teeth, thus approximating the closest to 
other Ungulates. 
One of the best known species is the North American mastodon (Mastodon 
americanus), of which teeth and bones, and sometimes entire skeletons, are found 
in enormous quantities in the peat and lacustrine deposits of Ohio and Missouri. 
This animal had enormous tusks in the upper jaw, but either none or mere 
rudiments in the lower jaw; and its molar teeth, with the exception of the last, 
had only three ridges, in which the longitudinal cleft was but slightly marked. 
Some of the teeth are so fresh-looking as to appear almost like those of recent 
elephants, and it seems that this mastodon lived on till within the human period. 
In height the skeleton stood about 12 feet at the shoulder. 
In the Old World mastodons disappeared at an earlier date, none being- 
known to have survived the close of the Pliocene period. Remains of several 
species occur in the Miocene and Pliocene deposits of the Continent, while 
detached teeth are occasionally found in the shelly deposits on the coast 
of Essex, Suffolk, and Norfolk, locally known as crags. In Northern India 
there were an extraordinary number of species of these animals; and among 
these the broad-toothed mastodon (M. latidens), ranging from India through 
Burma to Borneo, is the one approaching most closely to the elephants. In some 
of these Indian mastodons, as in one of those from the English crags, the inner 
and outer columns of the ridges of the molar teeth are completely separated from 
one another, and are arranged somewhat alternately; and from the nipple-like 
form assumed by these columns in the species in question, the generic name of 
Mastodon takes its origin. 
The Dinothere. 
Family I) I NO THERIIDAZ. 
A remarkable animal known as the dinothere (Dinotherium giganteum), the 
remains of which are found in the Miocene and Pliocene rocks of Europe and India, 
presents us with the most generalised type of Proboscidian yet known. In this 
animal, which must have been fully as large as an elephant, there appear to have 
been no upper tusks, but the extremity of the lower jaw was sharply bent down, 
and terminated in a pair of very massive and somewhat curved tusks. As in the 
elephants and mastodons, there were no canine teeth, and the cheek-teeth carried 
transverse ridges. The whole of the permanent series of cheek-teeth were, how¬ 
ever, in use at the same time, as in ordinary Ungulates, and their ridges were low 
and simple, and either two or three in number. Very little else is known of the 
skeleton of this strange animal, and there have been many conjectures as to the 
use of the downwardly-curved lower tusks. Possibly the creature may have been 
more or less aquatic in its habits, and have used these weapons to drag up water- 
plants from the beds and banks of lakes or rivers. On the other hand, it may 
