FALCOKEE— MASTODON AND ELEPHANT. 265 



Mastodon or Elephant. He has figured an instructive specimen, which 

 proves that the theoretical first or preantepenultimate milk-molar is 

 occasionally developed in the lower jaw of the African Elephant. 



Professor Owen has briefly described the ridge-characters of the 

 teeth of this species in the " Odontography," and assigns the fol- 

 lowing numbers to the ridges in the six successive molars, i. e. 

 4-|-7-f-7: 7-1- (8-9) +(10-12), the last of the ciphers being at- 

 tributed to the sixth (or last true) molar of the lower jaw. In this 

 estimate, the '' talon" is apparently reckoned in some of the cases 

 as one of the principal ridges. I have examined the specimens upon 

 which De BlainviUe's descriptions were founded, and various molars 

 of all ages in different collections contained in museums in this 

 country or abroad, and, excluding the two " talons," the ridge- 

 formula in the African Elephant has appeared to me to be thus : — 

 Milk-molars. True molars. 



3 + 6 + 7 7+ 8 +10 



3 + 6 + 7 7 + (8-9) + ll. 



The amount of development in the posterior talon is subject to con- 

 siderable variation. In some cases it forms merely an insignificant 

 splent appended to the last ridge ; in others it attains the propor- 

 tions of a reduced ridge, and, according to the degree of its evolu- 

 tion, it may be differently regarded by different naturalists, either 

 as a distinct ridge or as an appendage. The hypisomerous character 

 of the ridge-formula, in the intermediate molars of the Loxodons, is 

 exhibited by the succession of ciphers assigned above to the ridges 

 in the last mUk molar and the antepenultimate and penultimate 

 true molars, i. e. 7 + 7 + 8. I have seen specimens in which the 

 penultimate true molar of both the upper and lower jaws presented 

 nine ridges. Cuvier states that he had never observed a tooth of 

 the African Elephant showing more than ten plates. A last molar of 

 the upper jaw, left side, procured from Cape Coast by Mr. Samuel 

 Turner, exhibits, in a length of 11 inches, thirteen plates, i. e. eleven 

 principal ridges, besides front and back talons. 



The well-known and very constant distinctive characters in the 

 molars of the African Elephant consist of the rhomb-shaped pattern 

 yielded by the disks of the ridges after advanced wear, together with 

 the relative narrowness of the crowns as compared with those of 

 the Indian Elej)hant. The systematic signification of these peculia- 

 rities appears to me to be, that this species among the Loxodons 

 represents the groups of forms in Trilojyhodon and Tetralopliodon, 

 described in the preceding part, as having the ridges of their molars 

 characterized by outlying flanking tubercles and blocked-up valleys, 

 and as belonging to the " Stenocoronine" type. In the African 

 Elephant, the digital processes are less divided and more speedily 

 confluent than in the Mastodons : each ridge throws out, in front 

 and behind, a mesial angular projection, which meets or overlaps 

 the corresponding part of the next contiguous ridge; and the trans- 

 verse continuity of the valleys, which are filled up with cement, is 

 interrupted in consequence. The adjoining rhombs, in the process of 



