30 THE MASTODON. 



1. M. giganteus. This variety (sometimes called M, Amer- 

 icanus) has been sufficiently described in what has already 

 been said, for it has been taken as the predominant type. 



2. M. Tapiroides, This variety is named from its sup- 

 posed resemblance to the tapir, and approaches nearer the 

 31. giganteus than to any other species. Cuvier named it 

 from a single tooth found near Orleans, France ; other 

 teeth have been found in various places. Its peculiarity 

 consists principally in the formation of the prominences 

 of the molar-teeth, but being less notched than in the M. 

 giganteus. This species is said to form the connecting link 

 between the M. giganteus and the Dinotherium. 



3. Mastodons of South America. Two species are found 

 in South America: the 31. Humholdt'ms and 31. Andium; 

 both being considered by Cuvier, De Blainville, Owen, and 

 others, as referable to the 31. angustidens, or narrow- tooth 

 group. The 31. Humholdtlus was named from the celebra- 

 ted traveler, who discovered it. It has a shorter jaw than 

 the M. Andium, and the folds of the enamel are more com- 

 plicated than in the teeth of the 31. giganteus. It is also 

 found in New Mexico. The 31. Andium is a smaller species, 

 having the same undulating folds of enamel as the other, 

 but a more elongated symphysis. It also occurs in Central 

 America. 



4. 31. Angustidens. This name was given by Cuvier to 

 mastodons having narrower teeth than the 31. giganteus. 

 There is considerable dispute about this species, some 

 authors including under this group all the narrow-toothed 

 mastodons, while others number several species. Passing 

 over these disputes, its chief distinction may be said to be 

 that the two ultimate molars in the lower jaw have both 

 four ridges, and the horizontal branch in front of the 

 molars forms a long horizontal semi-canal, slightly inclined 

 downwards. Some anatomists point out other distinctions 

 in the skeleton. To this the 31. Turicensis is closely allied- 



