FEB., 1912. MAMMALS OF ILLINOIS AND WISCONSIN CORY. 447 



so, they hitch themselves along clumsily and with evident effort. 

 They vary greatly in size, from an animal smaller than a House Mouse 

 to the great (for this family) Pteropus edulis, a species inhabiting Java 

 and the Philippines 'and having a body the size of a small cat and a 

 wing expansion of nearly five feet. Many species are supplied with 

 odoriferous glands which are chiefly developed in the male. The 

 food varies in different species; some are largely insectivorous; others 

 frugivorous; and several exotic forms are sanguinivorous, but con- 

 trary to popular belief the last are all comparatively small. The 

 so-called Vampire Bats belonging to the genus Vampyrus, which for 

 many years were accused of sucking the blood of animals, are now 

 known to confine themselves almost entirely to fruit. 



Skeleton of a Bat. 



a, Pollex; b, metacarpals; c, phalanges; d, radius; e, ulna; f, an tebrachial membrane ; g, humerus; 

 h. scapula; i, clavicle; j, femur; k, tibia (fibula rudimentary and not shown); 1, calcar; m, interfemoral 

 membrane; n, tragus. 



Bats possess a wonderfully "developed tactile sense enabling them 

 to avoid objects in their flight, which is not perfectly understood. 

 It is supposed to be located in the highly sensitive network of nerves 

 of the wing membrane,* as well as in the ear conchs, in the vibrissae of 

 the muzzle and in some species the cutaneous expansions surrounding 

 the nostrils. Exceedingly slight changes in temperature or density of 



* The wing membrane is furnished above and below with exceedingly fine and 

 widely scattered hair, which, according to Schobl, aid in transmitting the exalted 

 sense of touch, while other nerve fibres give appreciation of temperature. 



