12 BULLETIN 43, UNITED STATES NATIONAL MUSEUM. 



THE HAIR. 



The hiiir of the body is arranged in regions having well-defined bound- 

 aries. The crown of the head, the region directly in front of the ear, 

 the neck, especially the side and back, inclusive of a line across the top 

 of the chest, the shoulder itself, the sides of the under surface of the 

 body, the rump, and pubis are all regions which are often sepaiately 

 colored, or clothed with hair of distinct texture, or rate of development 

 than that of the other portions of the body. The sides of the neck are 

 always furnished with longer hair than is the front and ordinarily than 

 is the back. The hair of the pubis is more woolly than that seen else- 

 where. The hair extends fiirther on the dorsum of the face in Vesper- 

 tilio than in most genera. The same region is naked in Adelonycteris. 

 The shoulders are occasionally furnished with shades of color contrast- 

 ing with that of the rest of the body. 



The membranes are clothed with hair in varying degrees. The greater 

 area is naked. The iuterfemoral juembraue is more thickly clothed on 

 the upper than the lower surface, a tendency reaching its maximum in 

 Atalapha, while the lower surface of the wing membrane between the 

 body and the border of the manus — a tendency also marked in Atalapha, 

 but most marked in the Asiatic form of the noctule bat {Xoctidina noc- 

 tiila lasiopterus). As a rule the fur from the under surface of the body 

 extends from the upper third or half of the arm to the knee. The 

 presence of a clump of hair on the dorsum of the forearm is a good 

 peripheral character for Atalapha cinerea. The iuterfemoral membrane 

 as a rule is covered with an extension of hair from the rumj) to the 

 basal third in Yespertilionidji^. In YesperUlio an interesting char- 

 acter is noted in the clump, not being well defined, but straggles down- 

 ward in an irregular manner and is lost near the ankle. This disposition 

 is especially developed in YespertiUo capaccini and in the J^Tevadan 

 variety of YesperUlio nitUlns ciUolahrum. The lower border of the 

 membrane is constantly fringed in some forms of YespertiUo, but as 

 an individual variation in the North American species. It is rare to 

 have the lower border of the wing membrane from the foot to the 

 manus fringed as in Pteropus, but YespertiUo, as seen in North 

 America exhibits a singularly constant, minute bristle which overlies 

 the membrane at the tip of the fifth finger. The ears are apt to be 

 sparsely haired on the inner surface near the anterior border, on the 

 outer surface at the basal third or half, and on the external basal lobe. 

 On the whole the bats which take the prone position in rest are less 

 heavily furred than those which are pendent. In one of the most 

 marked forms of the former group ( Gheiromeles) the skin is nearly naked. 

 Interesting contrasts can be made in this Avay between the haunters of 

 caves, attics, and old tree trunks and those which are caught hanging 

 from the smaller branches and twigs of trees and bushes. 



Bristles (setae) usually surmount warts (verrucse). They are best de- 

 veloped on the face of Molossi, though they may be found in the group 



