FOSSIL MAMMALIA FROM THE STONESFIELD SLATE. 417 



probably a small premolar, and the next two sockets are most 

 likely those of a double-fanged canine, such as we find in many 

 other mesozoic Mammalia. Four incisors account for the 

 anterior sockets. On the other hand, the type specimen (PI. 

 26, fig. 1) has six molars, and four molars beyond which the 

 jaw is broken; so that on combining the two we get the for- 

 mula i. 4, c. 1, pm. 5, m. 6.^ The dentition of A. Oweni 

 conforms perfectly to this ; we find four incisors, a double- 

 fanged canine, followed by eleven teeth, of which five were 

 probably premolars and six molars. This is also the conclu- 

 sion reached by Osborn (15) for the dental formula of Amphi- 

 therium. 



Genus Phascolotherium. 



There are three jaws belonging to this genus — the type 

 specimen in the British Museum, a specimen in the Oxford 

 Museum, and one in Mr. Parker's collection. They are all 

 placed in one species. 



Phascolotherium Bucklandi, Broderip. 



The type specimen, a right ramus with the inner surface 

 exposed, in the British Museum. 



This is the fossil mentioned above as having been obtained 

 by Mr. Broderip, together with the type specimen of Amphi- 

 therium, about 1814. It must, therefore, be the other of the 

 " two portions of the jaw of the Didelphys" which Buckland 

 tells us were seen by Cuvier (6). This jaw was lost for a time, 

 but, on being found again, was described and figured by 

 Broderip in the 'Zoological JournaP of 1828 (4). He there 

 described the teeth as consisting of seven grinders, one canine, 

 three incisors, and the alveolus of a fourth, naming the jaw 

 Didelphys Bucklandi. 



It has been figured by Buckland (6), by Blainville (2j, by 

 Owen (19—21, 23), and lastly by Osborn (14). 



* The second Oxford specimen is the only jaw which shows definite signs 

 of Laving had five premolars ; A. Oweni affords no certain evidence in this 

 respect. 



