292 MA.RSUPIALIA. 



Leptocladus dubius^ Owen\ 



This is the type species. 

 Hah. Europe (EnglaDd). 



47739. Part of the left ramus of the mandible, containing eight 

 {Fig.) cheek-teeth, of which the four first are probably premolars ; 

 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. iii. fig. 4. Beckles Collection. Purchased, 1876. 



Family SPALACOTHERIID^. 



Dentition (in type genus) : — 1. 1, C. \, Pm: + M. ^. The lower 

 true molars of the type genus closely resemble in structure those of 

 Ghrysochloris, consisting of a single column surmounted by three 

 cusps arranged in a V. The upper true molars described under the 

 name of Peralestes likewise agree with those of the same genus. 

 The lower true molars decrease in size posteriorly. Marsh ^ refers 

 the American Jurassic genus Menacodon to this family. 



Genus SPALACOTHERIUM, Owen \ 



The characters of this genus are the same as those of the family. 

 The so-called Peralestes (in which there are six upper true molars) 

 is probably founded upon the upper jaw of the present genus. 



Spalacotherium tricuspidens, Owen ^ 

 This is the type species. 

 Hah. Europe (England). 



46019. Fragment of the hinder part of the left ramus of the man- 

 {Fig.) dible, showing the last four true molars, together with 

 the impress in the matrix of the anterior portion of the 

 ramus ; from the Middle Purbeck group of Durdlestone 

 Bay, Swanage, Dorsetshire. This specimen (woodcut 

 fig. 43) is the type, and is figured by Owen in the ' Quart. 

 Journ. Geol. Soc' vol. x. p. 426, fig. 1, and also in his 

 'Mesozoic Mammalia ' (Mon. Pal. Soc), pi. i. fig. 32. 



Purchased, 1874. 



^ Mesozoic Mammalia (Mon. Pal. Soc), p. 53 (1871). 



2 Amer. Journ. ser. 3, vol. xxxiii. p. 340 (1887). 



3 Quart. Journ. Geol. Soc. vol. x. p. 4^6 (1854). ^ Loc. cit. 



