278 MARSUPIALIA. 



47744. Part of a left mandibular ramus, containing four cheek- 

 {Fig.) teeth, provisionally referred to this species ; from the 

 same locality. Figured by Owen, op. cit. pi. ii. fig. 12. 



BecJdes Collection. Purchased, 1876. 



47754. A left mandibular ramus with one cheek-tooth, which is 



(Fig.) provisionally referred to this species ; from the same 



locality. Figured by Owen, op. cit. pi. ii. fig. 13. If 



eventually proved distinct, the name P. minor is proposed 



by Owen for this specimen. Same history. 



The following specimen was provisionally referred by Owen 

 to this species, but is probably generically distinct. 



47743. Part of the symphysis and left ramus of a mandible con- 



(Fig.) taining the anterior teeth. Figured by Owen, op. cit. 



pi. ii. fig. 11. Same history. 



Family DIDELPHYIDJB. 



Dentition : — I. j, C. |, Pm. ^, M. g. Incisors very small and 

 sharp : canines large ; premolars compressed, the fourth being pre- 

 ceded by a milk-tooth which persists till a late period ; true molars 

 formed on the general type of those of Dasyurus, the lower ones 

 being differentiated into blade and talon. Five complete digits to 

 each foot ; an entepicondylar foramen to the humerus. 



Genus DIDELPHYS, Linn.^ 



Including : —Peratherium, Aymard '^. 



Amphiperatherium, Filhol ^. 



The characters of this genus usually available in the case of fossils 

 are identical with those of the family *. In existing forms the 

 lower true molars may either decrease ^ or increase ^ in size from 

 the first to the last, and the fourth lower premolar may be either 

 lower than or equal to each of the preceding ones. In the Tertiary 



^ Syst. Nat. ed. 12, vol. i. p. 71 (1766). — Amended from Didelphis. 



2 Ann. Soc. Agric. Sci. Le Puy, vol. xii. p. 248 (1848), teste Filhol. 



3 Ann. Sci. Nat. vol. x. art. 3, p. 201 (1879). 



* Chiro7iectes, except in the case of the existing species, could not be dis- 

 tinguished in a fossil state from Didelphijs. 

 ^ L. lanigera, D. philander. 

 ° I). jMsilla, I), crassicaudata, D. Uirneri, Chironectes. 



