276 MARSUPIALIA. 



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. 



Beckles 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. 

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

 Peralestes (Phascolestcs) 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 

 pm. 3 and pm. 4. 



Achyrodon nanus, Owen - . 



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

 cinum. 



Nab. Europe (England). 



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

 (Fig.} containing pmT3, 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. 



Beclcles Collection. Purcliased, 1876. 



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

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



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



Same history. 



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

 taining four true molars ; from the same locality. Figured 

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



1 Mesozoic Mammalia (Mon. Pal. Soc.), p. 37 (1871). 

 a Loc. cit 



