DIDELPHYS CRASSICAUDATA. 101 



the tip of the chin and also the tip of the muzzle on 

 either side, whitish ; on the cheeks, a little below the 

 eyes, is a yellowish patch which extends round the 

 angle of the mouth ; about one-third of the tail is 

 covered with fur of the same character and colour 

 as that on the body ; beyond this the tail is black, 

 excepting a small portion, about one inch in length 

 at the apex, which is white ; the hairs are short, 

 closely adpressed and scarcely hide the scales which 

 are beneath ; the fore portion of each foot is brown ; 

 the hairs covering the ears on the outer side are 

 brownish, and those on the inner side are yellow, 

 but towards the outer margin they are brown. The 

 hairs of the back have the basal half grey, and the 

 apical half ochreous, terminating in yellowish brown ; 

 on the belly and underside of the neck the hairs are 

 ochreous, faintly tinted with grey at the base. The 

 female has no pouch. 



Observations. The head of the D. crassicaudata 

 is shorter and less pointed than in most other opos- 

 sums ; the ears are unusually small, and the tail is 

 very thick. In the character of the fur also, this 

 species differs from most others, the hairs being rather 

 short and somewhat adpressed, and the soft under 

 ; fur being very scanty: the specimens observed by 

 ;Azara varied considerably in their colouring. It 

 inhabits Buenos Ayres and Paraguay. A specimen, 

 procured by Mr. Darwin at Maldonado, and from 

 which the above description is taken, weighed 14^ oz. 



