23Q Geological Society : — Anniversary of 1839. 



wanting to prove the animal a mammal^ still if the great majority 

 of them were present^ our judgment could not but be decided by 

 the preponderance of characters. Bat if all the above characters 

 of mammals are present, and all those of saurians absent, it seems 

 to be a wanton skepticism to doubt that the animal was really 



warm blooded. 



Now it was asserted by Mr. Owen, who brought this subject 

 before us, that this is the case ; that all the characters which I 

 have enumerated above exist in the Stonesfield jaws. If we 

 satisfy ourselves that this is the case, I do not see how we can 

 avoid assenting to his opinion, — that the animal belonged to the 

 class Mammalia. 



Every such question of classification must resolve itself into 

 two ; that of the value^ and that of the existence of the charac- 

 ters. If we assent to Mr. Owen in his view of the former, we 

 are then led to consider the latter. 



M. de Blainville, at least in his first examination, had labored 

 under the disadvantage of forming his judgments from casts and 

 drawings only of the Stonesfield bones. Under these circum- 

 stances, he had denied several of the above characters ; he had 

 held that the teeth in the Thylacotherium are uniform ; and that 

 they are confluent with the jaw ; and that the jaw is compound. 

 These statements Mr. Owen, resting upon a careful examniation 

 of the specimens, contradicts. The assertion of the compound 

 nature of the jaw is occasioned by a groove near the lower mar- 

 gin of the jaw, which however, is not so situated as to represerit 

 the saurian sutures, but is completely explained by supposing it 

 to be a vascular canal, such as exists in the Wombat, Didelphys 

 Opossum, and similar animals. 



Another specimen, at that time the property of Mr. Broderip, 

 but now very properly placed in the British Museum, exhibits a 

 jaw similar indeed to the Thylacothere, but belonging to a differ- 

 ent genus ; and to this species Mr. Owen has given the name 

 Phascolatherium Bncldandi. Both these generic names imply 

 that the animals are pouched animals ] and in addition to the rea- 

 sons which led Cuvier to this opinion, Mr. Owen has noticed in 

 the fossils an inflection of the lower edge of the jaw, which, so 

 far as has been hitherto observed, occurs in Marsupials^ and in 

 them alone. 



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