1890.] NATURAL SCIENCES OF PHILADELPHIA. 21 



Crown more blackish ; base of prebrachium same color as mantle. 



(3) Same as No. 1. 



Crown and mantle everywhere tawny, no yellow tints on body. 

 Chest and abdomen and base of prebrachium tawny throughout. 



(4) Same as No. 1. (smaller, probably immature). 

 Croivn rich chestnut. 



Back of neck (mantle) light-yellow verging to a paler hue. 



Base of prebrachium the same as back of neck. 



Side of neck, front of neck and shoulder at base of humerus light 

 chestnut. 



Front of cliest and side of trunk much the same but intermixed 

 with black points. 



Back with many dark chestnut points to the prevalent black 

 hair. 



(5) Same as No. 4. 



Front of chest and ahdovien nearly black. 



In P. medius it is clearly seen that the basal dark shades are more 

 persistent than the tips. The region of the crown becomes variable 

 as the chestnut 'and brown tips disappear and permit the basal 

 dark shades to show and give various effects to the general color of 

 the region. The back seems to be composed of the basal black — the 

 entire length of the hairs being about equal to the dark portions of 

 the hair of the side of the neck and of the mantle. 



In group No. 4. the prevalence of the lighter chestnut or yellow 

 shades are substitutions for the tip-colors only for the darker brown 

 or black of the other groups — with the exception of the base of the 

 prebrachium, where the hair is entirely yellow, as in group 3 it is 

 entirely tawny. 



Pteropus poliocephalus. 



Six skins of adults. 



Croxvn and face and region between the horizontal rami of man- 

 dible dark gray. Hair in front of the ear thicker than elsewhere 

 and verging to black. No basal contrast. The hair is thick and 

 long except on the face. 



Labial fringe absent. 



Side of neck with very long and soft chestnut-colored hair. The 

 base is black. 



