MASTODON. 387 



section of Mastodon- in which the first and second true molars 

 have each four transverse ridges,* and for which Dr. Falconer 

 proposes the name Tctralophodon. In the newer tertiary de- 

 posits of Xorth America remains of a Mastodon (M. Oliioticus) 

 have been discovered, in which the transverse ridges of the 

 grinders are in shape more like those of the Dinothere than 

 in any other Mastodon ; the first and second, moreover, have 

 two ridges, and the third, three ; but this is followed by two 

 three-ridged molars and a last larger molar with four or five 

 ridges.f For the Mastodons with three-ridged penultimate 

 and antepenultimate grinders, Dr. Falconer proposes the name 

 Trilojilwdon, In the Mastodon Oliioticus the lower jaw has 

 two tusks in the young of both sexes ; these are soon shed in 

 the female, but one of them is retained by the male (fig. 

 140, B). The upper tusks are long and retained in both 

 sexes (fig. 140, .4). { 



An almost entire skeleton of a Mastodon (M. turicensis, 

 rig. 140) has been discovered in the pliocene deposits of Aste, 

 Piedmont. The total length from the tail to the end of the 

 tusks is 17 feet. The teeth have the same narrow shape and 

 multi-mammillate structure as in M. avernemis, but in the 

 numerical character of transverse divisions of the crown this 

 species agrees with M. Oliioticus. 



The Mastodons were elephants with the grinding teeth 

 less complex in structure, and adapted for bruising coarser 

 vegetable substances. The grinding surface of the molars 

 (fig. 141), instead of being cleft into numerous thin plates, 

 was divided into wedge-shaped transverse ridges, and the 

 summits of these were subdivided into smaller cones, more 

 or less resembling the teats of a cow, whence the generic 

 name.§ A more important modification appeared to dis- 



* First demonstrated by Kaup, Ossemens Fossiles de Darmstadt, 4to, 1835. 



f Owen's " Odontography," 4to, 1845, p. 617, pi. 144. 



% Owen's " Odontography," p. (318. § Jfastos. a nipple: odous, a tooth. 



