430 LAND MAMMALS IN THE WESTERN HEMISPHERE 



remainder of the skeleton differed so little from that of the 

 elephants as to require no description. In size, this species 

 about equalled the fMammoth, the larger individuals measur- 

 ing nine feet six inches at the shoulder. Remains have been 

 found which prove that the American fMastodon had a cover- 

 ing of long, coarse hair, and that it fed upon the leaves, shoots 

 and small branches of trees, especially of conifers. There is 

 much reason to believe that the species outlived the elephants 

 in this continent and persisted until after the establishment 

 here of the American Indian, and it may well have been human 

 agency which finally extinguished the dwindling race. The 

 range of the species nearly coincided with that of the fColum- 

 bian Elephant, but did not extend so far into Mexico, and in 

 the central part of the continent reached much farther north, 

 even into Alaska. 



In the Pliocene of Texas, Nebraska and Idaho lived the 

 American representatives of a genus {'\Stegodon) which was a 

 connecting link between the elephants and the fmastodons, and 

 which was especially characteristic of the Pliocene of India. 

 The tusks, which were confined to the upper jaw, had lost- 

 their enamel and the last molar, above, and below, had five or 

 six enamel ridges, but the crowns, which in the Asiatic species 

 were buried in cement, had but a small amount of this 

 material. Several species of ^Mastodon occur in the same beds, 

 but only isolated teeth have been found. 



The fmastodons, in a broad sense of the term, have been 

 divided into several genera and subgenera in accordance with 

 different schemes; the simplest perhaps is to group into a 

 second genus those species which had fully developed lower 

 tusks. This four-tusked genus has received several names, 

 of which ^Tetrabelodon is most commonly used in this country, 

 but the term ^Gomphotherium is much older and, according 

 to the law of priority, must therefore be employed. The lower 

 Pliocene species of ^Gomphotherium had a pair of large lower 

 tusks, of cylindrical shape, and both upper and lower tusks 



