THE FOSSIL JAWS FROM STONESFIELD. 3 



" Doubts concerning the supposed fossil Didelphis from 

 Stonesfield, &c." 



This celebrated anatomist having had at his disposal only 

 the drawings of these interesting fossils, which are more or 

 less faithful representations, has nevertheless, with his usual 

 precise method of comparison, scrutinised the different parts 

 of these jaws; he has put forward in succession all the diffi- 

 culties to be overcome; and placed us in possession of the 

 doubts which the previous opinions had left in his mind : and 

 finishes by coming to this conclusion. 



First. — That it is not probable that the two solitary fossil 

 fragments from Stonesfield can belong to a mammal of the 

 genus Didelphis, or to a carnassier allied to the Insecti- 

 vora. 



Secondly. — That if we ought to regard them as belonging 

 to the class of mammals, their molar dentition would bring 

 them nearer to the family of the seals than to any other. 



Thirdly. — That it is more probable that they should be re- 

 ferred to a genus of the sub-order of saurians. 



Fourthly. — That in the present state of the case he propo- 

 ses to distinguish them under a distinct generic name, — that 

 of Amphitherium. 



We thus perceive that this distinguished professor of com- 

 parative anatomy is inclined to regard these vertebrated ani- 

 mals as more nearly allied to the Reptilia than to any other 

 class ; and he cites, in support of his conjectures, the opinion 

 of M. Agassiz, whom he believes to entertain the same views 

 of the matter as himself. 



I ought here to observe that the note extracted from a let- 

 ter of M. Agassiz which is placed at the head of No. 10 of 

 the 'Comptes Rendus de TAcademy,' seems in favour of this 

 opinion, since it says, — " M. Agassiz, on the occasion of a 

 recent communication from M. de Blainville, writes word that 

 subsequently to the year 1835, he has expressed, in Bronn 

 and Leonhard's Journal, (p. 186, anno 1835), an opinion per- 

 fectly agreeing with that of M. de Blainville concerning the 

 supposed Didelphis" In referring however to this quotation 

 I find that in this note M. Agassiz establishes, in a very clear 

 manner, the opinion that the Stonesfield animals are undoubt- 

 edly mammals, but that their affinity with the marsupials 

 does not appear to him to be so certain ; — that their teeth re- 

 semble more those of the Insectivora, and also have some re- 

 semblance to those of the seals. 



The object of M. Agassiz therefore in this note, is to show 

 that these bones are those of a mammal, which he considers 

 rather as belonging to the order Insectivora than to any other. 



b 2 



