194 Bulletin American Museum of Natural History. [Vol. XIII, 



Measurements. Total length (of type), 824 mm.; head and body, 371 ; tail, 

 453 ; hind foot, 57; ear (in dry skin), 26x26 (as against 32x32 in D. karkin- 

 ophaga and D. k. cauctz). 



Skull, total length, 94 ; basal length, J ; nasals, 46 ; palate, 54 ; 

 zygomatic breadth, 53 ; mastoid breadth, 27 ; interorbital breadth in front 

 of postorbital processes, 19, behind postorbital processes, n. Another 

 skull, of a very old male, measures, total length, 117; basal length, 109; 

 nasals, 55 ; palate, 66 ; zygomatic breadth, 61 ; mastoid breadth, 35 ; in- 

 terorbital breadth in front of postorbital processes, 23, behind postorbital pro- 

 cesses, 10.5. 



As shown by the subjoined table, the Santa Marta form aver- 

 ages considerably smaller than the Trinidad form. 



EXTERNAL MEASUREMENTS OF Didelphis karkinophaga colombica. 



Hind 

 Foot. 



57 

 68 



57 

 57 

 54 

 57 

 57 



60 

 56 



Metachirus fuscogriseus, sp. nov. 



Type, No. f|f|, $ ad., Central America ; presented by Albert Smith. 



Above dusky, the tips of the hairs silvery, the general effect being blackish 

 with a grayish wash ; whole top of the head and a more or less distinct median 

 band black ; sides lighter with more gray, the color of the dorsal surface sharply 

 defined against the pale yellowish white of the ventral surface ; supraocular 

 spots pale yellowish white, with a narrow band of the same color at the base of 

 the ears above, and a broader band of the same below the ears ; cheeks, throat, 

 and fore neck rather more strongly yellowish white than the rest of the ventral 

 surface ; outer surface of fore and hind limbs like the sides but rather paler ; 

 the inner surface of the limbs like the ventral surface; feet nearly naked, 

 brownish both above and below ; ears apparently flesh-color in life, broadly 

 edged with dark brown ; tail heavily furred for about the first (proximal) inch 

 and a half ; the rest naked, dark brown basally, gradually becoming lighter api- 

 cally, the last two or three inches being light brown, perhaps flesh-color in life 

 at the tip. 



Base of skull imperfect. 



