292 PROBOSCIDIA. 



linear lines are well displayed at the fractured surface of 

 this end, figured at c. The transverse section of this tusk 

 (fig. 101, I) gives an irregular oval figure, one side being less 

 convex than the other ; and on the lower half of the less 

 convex (outer) side of the tusk, faint traces may he distin- 

 guished of longitudinal grooves, about a line in breadth : 

 the slender subcentral canal is nearer the lower than the 

 upper surface of the tusk. In all these characters, the 

 fragment in question agrees with a similar fragment of a 

 tusk, ten inches in length, obtained from the miocene, or 

 older pliocene tertiary deposits at Eppelsheim, and now in 

 the collection of the Earl of Enniskillen ; which specimen 

 Dr. Kaup has determined to belong to the lower jaw of 

 his Mastodon longirostris, the Mastodon angustidens of 

 Cuvier. 



The earliest observation of this striking character of in- 

 ferior tusks, which distinguishes the genus Mastodon from 

 Elephas, appears to have been made by Dr. Godman, in 

 1829,* upon a mutilated lower jaw of a young Mastodon 

 giganteus, obtained, I believe, from tertiary deposits in 

 Orange County, United States, and at that period in 

 Peale's Museum, New York. The symphysis of this jaw 

 was entire, and contained two short tusks, from four to 

 six inches in length, projecting straight forwards from the 

 extremity of that part of the jaw. As the lower jaws of 

 the mature American Mastodons which were at that time 

 known to science, offered, like those of the species of 

 Elephant, no trace of tusks, Dr. Godman described his 

 specimen as belonging to an extinct animal of a new 

 genus, for which he proposed the name of Tetracaulodon. 

 Mr. Cooper of New York, however, "suggested the opinion 

 that the Tetracaulodon was nothing but the young of the 



* Transactions of the American Philosophical Society, vol. iii, N. S. p. 478. 



