1900.] Allen, New American Marsupials. 1 93 



described below, is recognizable not only through differences of 

 color, but in having the ears at least one third smaller than in 

 either of the other forms. In each form the ears are wholly 

 black. The Trinidad form is much the larger, as shown by the 

 following average measurements of four adult males and three 

 adult females. Males : Total length, 874 mm.; head and body, 

 452; tail, 446; hind foot, 60.5. Females: Total length, 807 ; 

 head and body, 406 ; tail, 401 ; hind foot, 57. While in the 

 average the tail measures less than the head and body, there are 

 several exceptions where the tail considerably exceeds the head 

 and body, as in No. 6063, $ , where the tail measures 465 and 

 the head and body 455 ; No. 6051, $ , tail 425, head and body, 

 385 ; and No. 7732, ?, tail 430 and the head and body 40O. 1 

 It is therefore doubtful whether in any of the forms of Didel- 

 phis the tail regularly exceeds the head and body in length. 



There is also considerable variation in respect to the preva- 

 lence of black or white hairs in the pelage of the dorsal surface 

 in all the forms, in some examples the long white overhairs are 

 so abundant as to render the prevailing color whitish ; in other 

 examples they are nearly absent, leaving the prevailing color 

 blackish. 



The color differences in these three forms are quite as strongly 

 shown in young specimens, not more than one quarter grown, as 

 in the adults. 



Didelphis karkinophaga colombica, subsp. nov. 



Type, No. 15453, $ a d., Bonda, Santa Marta, Colombia, April 19, 1899 ; 

 coll. H. H. Smith. 



Similar to D. karkinophaga cattccz but darker throughout, the underfur a 

 deeper shade of buffy white, and the ears much smaller. Above the long over- 

 hair is more abundant and of a brownish black, often heavily mixed with stiff, 

 longer white hairs, but frequently the latter are wholly wanting ; head without 

 very distinct markings but with a tendency to an indistinct median stripe and 

 a lateral one on each side, more distinctly developed behind the eyes ; whole 

 top of the head, however, with the hairs more or less tipped with brownish 

 black, giving a general blackish grizzled effect ; ventral surface more deeply 

 buff, overlaid with a blackish grizzle produced by black-tipped hairs ; ears and 

 feet brownish black; tail black for about the basal half, the rest yellowish 

 white. 



1 See table of measurements given in this Bulletin, Vol. IX, 1897, p. 25. 

 October, iqoo.] IS 



