FOSSIL MAMMALIA FROM THE STONESFIELD SLATE. 411 



seals possessing tricuspid molars. Owen mentions (20) that 

 Agassiz proposed the name Amphigonus for Amphitherium, in 

 the German translation of Buckland^s Bridgewater Treatise 

 (which I have not seen). 



Dr. Buckland, in 1836, gave a rough figure of this jaw, to- 

 gether with enlarged drawings of two of the teeth (6). 



Two years later M. de Blainville published his " Doutes sur 

 le pretendu Didelphe de Stonesfield " (2), in which he tried to 

 prove that the fossil in question, of which he reproduced Buck- 

 land's figure, belonged to a reptile. In this paper he laid 

 considerable stress on the fact that " une portion de machoire 

 inferieure, rapportee de Stonesfield par M. Brochant de Villiers 

 et ses eleves MM. Elie de Beaumont et Dufrenoy, et qu'on 

 avait supposee appartenir au meme Didelphe," had been proved 

 to be reptilian, and accepted as such even by Cuvier. Blain- 

 ville mistook the mylohyoid groove,^ well marked in our speci- 

 men, for a suture indicating that the jaw was of a compound 

 structure : a similar mistake was made in the case of the other 

 jaws. He proposed the generic name Amphitherium, which 

 has since been generally adopted. 



Buckland then took with him to Paris the type specimen of 

 Amphitherium and the second fossil of the same species now 

 in the Oxford Museum, which will be described below. He 

 showed these to M. Valenciennes, who made a careful study 

 of them, publishing a detailed account mainly confirming the 

 results of Cuvier and Prevost, in which the name Thylaco- 

 therium Prevostii is proposed (31). Unfortunately Blain- 

 ville was not convinced, as he did not see the fossils, for he tells 

 us that "\q jour ou M. le docteur Koberton voulut bieu 

 m'inviter a passer la soiree chez lui avec M. Buckland, je 

 partais pour la campagne^' (3). He therefore only brought 

 forward " Nouveaux doutes '' (3), in which we learn that " M. 

 Buckland lui-meme a expose le probleme et les pieces sur les- 

 quelles il repose a ^investigation des naturalistes alleraands 

 reunis en congres a Fribourg, en Brisgaw, au mois de sep- 

 tembre dernier '' (1838). In his contention as to the saurian 

 ' For a full discussion of the mylohyoid groove see Osborn (14). 



