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



larger, measuring, total length, 99 ; basal length, 94 ; nasals, 48 ; zygomatic 

 breadth, 50. Other female karkinophaga skulls from Trinidad are still larger, 

 but otherwise than in size there seems to be no very noticeable difference, ex- 

 cept that in D. pernigra the bones are very smooth, dense, and heavy in 

 comparison with other Didelphis skulls. 



Didelphis pernigra is based on two adult females and one 

 young male. In style of markings and coloration they are all 

 remarkably uniform, and appear to be eminently distinct from 

 any other known forms of Didelphis. 



Didelphis karkinophaga caucae, subsp. nov. 



Type, No. 14192, ? ad., Call, Upper Cauca Valley, Colombia; coll. J. H. 

 Batty. 



Similar to D. karkinophaga from Trinidad, but darker colored throughout. 

 Underfur whitish or yellowish white, more or less hidden by long black-tipped 

 hairs, intermixed with long, wholly white bristly hairs, the abundance of the 

 latter variable in different specimens ; ventral surface buffy white, often inclin- 

 ing to rusty, the hairs tipped with blackish, so as often to give a grizzled black- 

 ish effect, wholly lacking in karkinophaga; head with a narrow blackish 

 eyering, and no other distinct blackish markings, but with a general grizzled 

 blackish effect over the whole head, the longer hairs being tipped with black, 

 instead of almost wholly whitish as in karkinophaga ; ears very large and 

 wholly deep black ; tail particolored, black at base and white for about the 

 apical half. 



Measurements. Total length (of type), 740 mm.; head and body, 370 ; tail, 

 370 ; hind foot, 58 ; ear (in dry skin), 32 x 32. A male (young adult), measures, 

 total length, 770 ; head and body, 410 ; tail, 360 ; hind foot, 53. Judging by 

 the material in hand, skulls and skins (eleven specimens), the skins mostly with- 

 out measurements of the fresh specimen, the Cauca Valley form of Didelphis 

 is considerably smaller than the Trinidad animal, with a relatively shorter tail. 



Skull rather broader than in true karkinophaga, but not otherwise different. 

 Total length (of type), 94 ; basal length, 87 ; nasals, 45 ; palate, 55 ; zygo- 

 matic breadth, 50 ; interorbital breadth in front of postorbital processes, 19, 

 behind postorbital processes, n. 



I have been rather surprised to find that series of specimens 

 of the karkinophaga type of Didelphis from, respectively, the 

 Island of Trinidad, Santa Marta, Colombia, and the Upper 

 Cauca Valley, Colombia, present color differences that are obvi- 

 ous on even superficial inspection. These series number from 

 eight to fourteen specimens each, and are all referable at a 

 glance to their respective series ; these forms hence seem en- 

 titled to recognition in nomenclature. The Santa Marta series 



