276 MARSTJPIALIA. 



from the same locality. Most of the anterior teeth and 

 the eight true molars (except the 6th) are shown ; the 

 true molars are less worn than in the preceding specimen, 

 and thereby show a taller anterior lobe of the blade, which 

 approaches that of Achyrodon ; the length of the space 

 occupied by the eight true molars is 0,008. 



BecMes Collection. Purchased, 1876. 

 47741. The greater part of the left ramus of a very similar mandible, 

 (Fig.) containing the incisors, canine, the four premolars, and 

 the first five true molars ; from the same locality. 

 Pigured by Owen, op. cit. pi. ii. fig. 4, under the name of 

 Peralestes -(Phascolestes) longirostris, but apparently pre- 

 senting no characters by which it can be distinguished 

 from the type specimen of the present form. The three 

 impressions in the matrix behind the sixth molar men- 

 tioned by Owen as being made by teeth appear to be of an 

 entirely different origin. Same history. 



Genus ACHYRODON, Owen \ 

 This genus appears closely allied to the preceding, but is distin- 

 guished by the greater height and more oblique direction of the 

 anterior lobe of the blade of the lower true molars, and the stouter 

 pmTS and pm. 4. 



Achyrodon nanus, Owen ^ 

 This (the type) species is rather smaller than AmUotherium sori- 

 cinum. 



Hah. Europe (England). 



47745. The middle portion of the right ramus of the mandible, 

 {Fig.) containing pm. 3, pm. 4, and the eight true molars ; from 



the Middle Purbeck group of Durdlestone Bay, Swanage, 

 Dorsetshire. This specimen, which is the type, is figured 

 by Owen in his ' Mesozoic Mammalia,' pi. ii. fig. 5. . 



Becldes Collection. Purchased, 1876. 



47746. Part of the left ramus of the mandible, containing p^^, 

 (Fig.) pm. 4, and the first five true molars; from the same 



locality. Figured by Owen, op. cit. pi. ii. fig. 6. 



Same histoty, 

 47783. The greater part of the left ramus of the mandible, con- 

 (Fig.) taining four true molars ; from the same locality. Figured 



by Owen, ojo. cit. pi. ii. fig. 7. Same history. 



^ Mesozuic Mammalia (Mon. Pal. Soc), p. 37 (1871). 

 ^ Log. cit. 



