258 MAESTJPIALIA. 



Genus TRICONODON, Owen K 



Including Triacanthodon, Owen ^. 



The characters of the genus are those of the family. The discovery 

 of specimens of Triconodon mordaoc with four true molars has 

 shown that the so-called Triacanthodon is not separable. 



In the American Upper Jurassic a species of this genus is recorded 

 by Marsh ^, the genus Priacodon being made for an allied form. 



Triconodon mordax, Owen \ 



Syn. (?) Triacanthodon serrula, Owen '. 



This is the type species ; the length of the space occupied by i^TTT + 

 m. 2 in the type specimen is 0,095, and that by ^7T + mr2 + mTS 

 0,008. At least in many adult specimens there were four lower true 

 molars, but it is not improbable that in other examples ^^ was 

 never developed. 



Hah. Europe (England). 



The following specimens (or their originals) luere obtained from the 

 Middle FurbecJc group of Durdlestone Bay, Swanage, Dorset- 

 shire. 



47766. The nearly entire left ramus of the mandible of a subadult 



(Fig.) individual, containing the anterior teeth and the first three 



true molars. This specimen (woodcut, fig. 38) is the type, 



Fig. 38. 



Triconodon mordax- The left ramus of the mandible (reversed) : from the 

 Purbeck of Swanage. \. 



and is figured by Owen in the ' Encyclopaedia Britannica,' 

 8th ed. vol. xvii. p. ] 61, fig. 86, and in his ' Mesozoic 

 Mammalia,' pi. iii. figs. 7, 7a. 



Beclcles Collection. Purchased, 1876. 



' Encyclopasdia Britannica, 8th ed. vol. xvii. p. 161 (1859). 

 ^ Mesozoic Mammalia (Mon. Pal. Soc), p. 72 (1871). 

 ^ Amer. Jouru. ser. 3, vol. xxxiii. p. 343 (1887). 

 * Encyclopaedia Britannica, loc. cit. 

 " Mesozoic Mammalia, loc. cit. 



