14.2 Geological Society : — Prof. Owen on the Jatas of 



having eleven molars in each ramus of the lower jaw, reserving to a 

 future occasion an account of the remains of the other genus*. 



Mr. Owen commences by observing that the scientific world pos- 

 sesses ample experience of the truth and tact with which the illus- 

 trious Cuvier formed his judgements of the affinities of an extinct 

 animal from the inspection of a fossil fragment ; and that it is only 

 when so distinguished a comparative anatomist as M. de Blainville 

 questions the determinations, that it becomes the duty of those who 

 possess the means to investigate the nature of the doubts, and re- 

 assure the confidence of geologists in their great guide. 



When Cuvier first hastily examined at Oxford, in 1818, one of 

 the jaws described in this paper, and in the possession of Dr. Buck- 

 land, he decided that it was allied to the Didelphys (me sembl^rent 

 de quelque Didelphef) ; and when doubts were raised by M. Con- 

 stant Prevost, in 18241, relative to the age of the Stonesfield slate, 

 Cuvier, from an examination of a drawing made for the express pur- 

 pose, was confirmed in his former determination ; but he added, that 

 the jaw diflfers from that of all known carnivorous MammaUa, in ha- 

 ving ten molars in a series in the lower jaw: (" il [the drawing] mecon- 

 firme dans I'idee que la premiere inspection m'en avoit donnee. C'est 

 ceUe d'un petit carnassier dont les machelieres ressemblent beaucoup 

 a celles des sarigues ; mais il y a dix de ces dents en serie, nombre 

 que ne montre aucun carnassier connu." Oss. Foss. 111. 349. note.) 

 It is to be regretted that the particular data, mth the exception of 

 the number of the teeth, on which Cuvier based his opinion, were not 

 detailed ; but he must have been well aware that the grounds of his 

 belief would be obvious, on an inspection of the fossil, to every com- 

 petent anatomist : it is also to be regretted that he did not assign to 

 the fossil a generic name, and thereby have prevented much of the 

 reasoning founded on the supposition that he considered it to have 

 belonged to a true Didelphys. 



Mr. Owen then proceeded to describe the structure of the jaw ; 

 and he stated that having had in his possession two specimens of the 

 Thylacotherium Prevostii belonging to Dr. Buckland,he has no hesi- 

 tation in declaring that their condition is such as to enable any ana- 

 tomist conversant with the established generalizations in compara- 

 tive osteology, to pronounce therefrom not only the class but the 

 more restricted group of animals to which they have belonged. The 

 specimens plainly reveal, first, a convex articular condyle ; secondly, 

 a well- defined impression of what was once a broad, thin, high, and 

 slightly recurved, triangular, coronoid process, rising immediately 

 anterior to the condyle, having its basis extended over the whole of 

 the interspace between the condyle and the commencement of the 

 molar series, and having a vertical diameter equal to that of the ho- 

 rizontal ramus of the jaw itself : this impression also exhibits traces 



* This has since been read, and an abstract of it will appear in our next 

 number. — Edit. 



+ Ossemens Foss., tome iii. p. 349. 



X Annales des Sciences Nat., Avril, 1825; also the papers of Mr. Bro- 

 derip and Dr. Fitton in the Zoological Journal, 1828, vol. iii., p. 409. 



