8& 
jority of them were present, our judgment could not but be decided 
by the preponderance of characters. But if all the above characters 
of mammals are present, and all those of saurians absent, it seems 
to be a wanton scepticism to doubt that the animal was really warm- 
blooded. 
Now it was asserted by Mr Owen, who brought this subject be- 
fore us, that this is the case; that all the characters which I have 
enumerated above exist in the Stonesfield jaws. If we satisfy our- 
selves 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 characters. 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 laboured 
under the disadvantage of forming his judgments from casts and 
drawings only of the Stonesfield bones. Under these circumstances, 
he had denied several of the above characters; he had held that the 
teeth in the Thylacotherium are uniform; and that they are con- 
fluent with the jaw; and that the jaw is compound. These state- 
ments Mr. Owen, resting upon a careful examination of the speci- 
mens, contradicts. ‘The assertion of the compound nature of the 
jaw is occasioned by a groove near the lower margin of the jaw, 
which however is not so situated as to represent 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 ani- 
mals. 
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 different 
genus ; and to this species Mr. Owen has given the name Phasco- 
lotherium Buckland. Both these generic names imply that the 
animals are pouched animals; and in addition to the reasons which 
led Cuvier to this opinion, Mr. Owen has noticed in the fossils an in- 
flection of the lower edge of the jaw, which, so far as has been 
hitherto observed, occurs in Marsupials, and in them alone. 
As if this question had been destined to be settled at this time, 
the only remaining doubt with regard to the possible existence of 
