AMPHITHERIIB^!. 277 



47785. Hinder part of the right ramus of the mandible, showing 

 five true molars ; from the same locality. 



Eeckles Collection. Purchased, 1876. 



Achyrodon pusillus, Owen \ 



Distinguished from the preceding species by the structure of the 

 mandible and teeth. 



Hal. Europe (England). 



47747. Fragment of the left ramus of the mandible, containing one 

 (Fig.) tooth ; from the Middle Purbeck group of Durdlestone 

 Bay, Swanage, Dorsetshire. This specimen is the type, 

 and is figured by Owen in his Mesozoic Mammalia' 

 (Mon. Pal. Soc.), pi. ii. fig. 8 : at that time there were four 

 cheek-teeth preserved. 



BecUes Collection. Purchased, 1876. 



Specifically undetermined specimen. 



48401. Fragment of a mandibular ramus with four true molars, 

 probably belonging to a small species of the present genus ; 

 from the Middle Purbeck group of Durdlestone Bay, 

 Swanage, Dorsetshire. 



Beckles Collection. Purchased, 1876. 



Genus PERAMUS, Owen 2 . 



The lower true molars are relatively stouter, and their blade 

 proportionally wider than in either of the preceding genera ; the 

 complete dental formula is unknown. 



Peramus tenuirostris, Owen 3 . 



This is the type species. 

 Hob. Europe (England). 



47742. The left ramus of the mandible, containing the last four 



(Fig.) cheek-teeth ; from the Middle Purbeck group of Durdle- 



stone Bay, Swanage, Dorsetshire. This specimen is the 



type, and is figured by Owen in his ' Mesozoic Mammalia ' 



(Mon. Pal. Soc.), pi. ii. fig. 10. 



Beckles Collection. Purchased, 1876. 



1 Mesozoic Mammalia (Mon. Pal. Soc.), p. 39 (1871). 

 3 Ibid. p. 41 (1871). 

 3 Loc. cit. 



