14 PROCEEDINGS OF THE ACADEMY OF [1890. 



of the side of the neck, of the side of the front of the body, or be a 

 special development. 



The side of the trimk, next to the side of the neck, is the most impor- 

 tant region. It appears to be controlled by the position of the mamma, 

 since the tract begins at the upper border of the gland. In Cynop- 

 terus marginatns it is confined to the region of the mamma. It ex- 

 tends in all forms, other than the one named, the entire length 

 of the trunk, becomes woolly and is lost on the inguinal, femoral or 

 crural regions. This tract apjiears to be the same as the region for the 

 colors on the flanks and inner surfaces of the legs of quadrupeds gener- 

 ally. It is undoubtedly sexual in significance, for in addition to its 

 relation to the mamma it lines the depression between the sides of 

 the body and the wing-membrane and forms a sort of pouch in 

 which the young are carried. The hair is uniformly soft and silky. 



The hair of the front of the trunk is shorter than that of the side, 

 and usually of varyingly contrasted shades of color. 



The back of the trunk begins at the level of the prebrachia, usu- 

 ally by a sharply contrasted line with the back of the neck ; but it 

 may be continuous with that of this region as in Cynopterus, or be 

 separated therefrom by a vertebral stripe, as in Harpyia, or by a nar- 

 rowed tract, as in Pteropus vielanopogon. When hairless (in the 

 adult), as in Cephalotes, the region is still sharply limited by the lines 

 of the prebrachia. 



The re^io'rt o/^Ae sacrum is conveniently separated from that of 

 the back since hair may be retained here when it is absent or rudi- 

 mental elsewhere, as in Cephalotes and P. ynelanopogon. 



The " rump" includes the region last named and the loin. 



The infra-anal region is not separated by any limit from the side 

 of the trunk but it is sometimes useful to speak of it distinctively. 



The shades on a single hair whether unicolored, or having the tip 

 of a different color from the shaft, or the base of a different color 

 from the shaft or tip, is always to be noted. The hair which extends 

 from the body to the auricles, the wing-membranes and the inter- 

 femoral membrane, is uniformly unicolored. The arm may be an 

 exception, when it is covered with the hair of the front of the trunk. 

 The hair at the front of the crown and sides of the face is generally 

 unicolored, as also is the" whisker." On the side of the neck the 

 hair may be unicolored when elsewhere the hair is bi-colored. 



