55 8 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. lot ideas), 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 DlNOTHERIW^E. 



A remarkable animal known as the dinothere (Dinotlierium 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 yery 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 



