308 PROCEEDINGS OF THE AMERICAN ACADEMY 



Mastodon, &c., presenting an unusual and grotesque appearance. In 

 this position they were first represented by Professor Kaup, who tells 

 us, that, while a friend of his was handling this anterior fragment of the 

 lower jaw containing the curved tusks, he accidentally turned it down- 

 wards, and found it corresponded exactly with the other fragment. 



" Then, for the first time, it was seen that this was the true natural 

 direction of the tusk, and that it probably served the purpose of a 

 pick to dig up food. Dr. Buckland suggests, that it might also be em- 

 ployed to anchor the head to the river-shore while the animal slept. 

 The curved tusk with the bone in which it is socketed forms a hook 

 about three feet in length, and the degree of curvature thus formed is 

 the fourth of a circle. 



" Teeth. — There are two sets of teeth ; — first, the primary or milk 

 teeth, twelve in number, three on each side of each jaw ; second, the 

 permanent, twenty in number, five on each side of each jaw. The 

 latter are divided into pre-molars and true molars ; the pre-molars are 

 the two in front, as the name indicates, making the whole number of 

 pre-molars to be eight. The true molars are twelve in number, three 

 .on each side of each jaw, placed behind the pre-molars. These teeth 

 resemble the Mastodon teeth in having two or three transverse ridges, 

 but differ from them in this, that they are all square excepting the first 

 true molar, which has three ridges and an oblong form. In the Mas- 

 todon, all the true molars possess an oblong form, particularly the last. 

 The middle permanent tooth of the Dinotherium, however, is some- 

 times distinguished with difficulty from the third or fourth tooth of the 

 M. giganteus. 



" The teeth of the Dinotherium are developed vertically, as in man 

 and most Mammalia. In this respect they differ from the Elephant 

 family, which, on account of the great size and weight of these or- 

 gans, have them developed horizontally. 



" Trunk. — Many bones of the trunk and extremities of this animal 

 have been discovered, but nothing like a complete skeleton. Some of 

 these bones are said to be of great size, exceeding corresponding 

 bones of the Mastodon and Elephant even by one fifth. The head of 

 the Dinotherium giganteum of Klipstein is, however, scarcely equal 

 in dimensions to that of the great Mastodon skeleton in Boston, or that 

 of the head in my possession, called, from the river near which it was 

 found, the Shawangunk head. The body is represented by learned au- 

 thors to be eighteen feet long, which is two feet longer than our largest 



