52 NEW DOUBTS RESPECTING 



M. de Blainville also quotes the second note of M. Agassiz, which, 

 though longer, adds scarcely anything to the contents of the first; ex- 

 cept that M. Agassiz very justly remarks that M. Cuvier, in speaking 

 of these fossils, never positively affirmed that they ought to rank in the 

 genus Didelphis ; and he [M. Agassiz] proposes to designate the ge- 

 nus by the name of Amphigonus, 



From these two passages we may infer, that prior to his 

 having actually seen these fossils, M. Agassiz had supposed 

 that they might belong to a fish ; an opinion which he has 

 abandoned to refer them decidedly to the class Mammalia. 



Thus, as M. Valenciennes properly observes, it would be 

 unjust in M. Agassiz to lay claim to the opposite opinion ; 

 although in fact neither of these articles has for its object the 

 establishing, in a direct manner, that these remains from 

 Stonesfield are those of mammals; as M. Valenciennes ne- 

 vertheless observes. We may, on the contrary, find there the 

 assertion, though destitute of proofs, that the dental system 

 of the supposed Didelphis of Stonesfield is too far removed 

 from that of the marsupials to allow of our placing it in that 

 sub-class ; and that if, regarded in its totality, it bears a cer- 

 tain resemblance to what we find in the Insectivora, the pos- 

 terior teeth in particular may also be compared to those of 

 certain seals. He thus leans towards the opinion that it is 

 rather an aquatic than a terrestrial animal, considering it as 

 approaching to the seals. We there also find that M. Agas- 

 siz was of opinion that these fossils ought to form a distinct 

 genus ; but that he did not propose for this genus the name 

 Amphigonus until his second note ; of this, indeed I, was ig- 

 norant, as M. Valenciennes very correctly observes, nor could 

 I possibly have known it, since this note, if it were printed 

 at the time my memoir was read, was certainly not published. 



Finally, I ought to notice a very just observation of M. 

 Agassiz, which is, that M. G. Cuvier, in speaking of these 

 fossils, always retained a doubtful form of expression, or at 

 least very slightly affirmative, and such as would follow from 

 a very rapid and consequently slight examination. 



But of the four communications made to the Academy re- 

 lating to the supposed Didelphis from Stonesfield, that of M. 

 Valenciennes must necessarily occupy the first place, as be- 

 ing the longest. In fact, Dr. Buckland, who from the first 

 intrusted these fossils to M. Laurillard, that is to say, not 

 only the specimen upon which rests the Did. Prevostii of M. 

 Cuvier, but also another, in some respects more complete, and 

 of which no one had previously spoken ; — at the particular 

 request of M. Valenciennes, very obligingly allowed him to 

 make them the subject of his observations, and even to take 



