1!)2 Mr. Owen on the Mammalian Remains, 



molar bears exactly the same proportion tothe above-mentioned 

 fossil posterior molar, which obtains in the corresponding 

 teeth of the recent Macaci, I have no doubt that the two fossil 

 teeth belong to the same extinct species of Macacus* 



The inferior molars in the genus Didelphys differ from the 

 tooth in question in having the anterior and external angle cut 

 off as it were vertically. 



2 . A portion of Jaw with one of the False Molars of a Mam- 

 miferous Species, probably allied to the Genus Didelphys. 

 (Fig. 2.) 



There is no tooth so little characteristic, or upon which a 

 determination of the genus could be less safely founded, than 

 one of the false molars of the smaller carnivorous and omnivo- 

 rous Ferce and Marsupialia. A large, laterally compressed, 

 sharp-pointed middle cone or cusp, with a small posterior, and 

 sometimes also a small anterior talon, more or less distinctly 

 developed, is the form common to these teeth in many genera 

 of the above orders. It is on this account, and because the 

 tooth of the fossil in question (fig. 2 a.) dif- Fig. 2 a. 



fers in the shape of the middle and size of 

 the accessory cusps from that of any known 

 species of Didelphys, that I regard its refer- 

 ence to that genus as premature, and the affi- 

 nities of the species to which it belongs as outside, nat. size, 

 awaiting further evidence before they can be determined be- 

 yond the reach of doubt. Mr. Charlesworth, by whom the 

 present fossil w r as first described and figured*, has accurately 

 specified the differences above alluded to in the shape of the 

 crown of the tooth as compared with the false molars of the 

 true Opossums : they are seen in the more equilateral or sym- 

 metrical shape of the middle cusp, the greater development of 

 the posterior talon, and the presence of the anterior talon at 

 the base of the middle cusp : the grounds on which his de- 

 termination of the fossil was founded are not stated. 



I agree, however, with Mr. Charlesworth, so far as to con- 

 sider the fossil in question as bearing so close a resemblance 



* Mag. of Nat. Hist., September 183<J. 



