642 



CHIROPTERA. 



Among the marsupials (Petaurus), the rodents (Pteromys) 

 and the insectivores (Galeopithecus), there is a number of forms 

 which are assisted in jumping by a kind of parachute, which 

 consists of a cutaneous expansion, the patagium, stretched be- 

 tween the limbs on each side. The patagium is much more 

 completely developed in the bats ; in these animals it is con- 

 tinued over the extraordinarily elongated fingers of the hand, 

 and in virtue of its great size and elasticity constitutes a true 

 organ of flight. The tail, when present, is included in the pata- 

 gium, but the thumb and the foot are separate from it (Fig. 326). 



FIG. 326. Skeleton of Pteropus (after Owen, slightly altered). Cl clavicle ; D thumb ; F 

 fibula ; -Fe^femur ; Jl ilium ; Js ischium ; H humerus ; P pubis ; R radius ; Sc scapula ; 

 St sternum ; T^tibia ; U ulna. 



Both fore- and hind-limbs are pentadactyle. The thumb has 

 two phalanges and is armed with a claw, as are also the five 

 digits of the foot (Fig. 326). The second digit of the, manus 

 is also, in some forms, provided with a claw. 



Peculiar outgrowths Jof the skin surrounding the nasal aper- 

 tures (nose-leaf) are often present and give the face a very 

 strange appearance (Fig. 327). Except upon these appendages 

 and upon the thin elastic patagia, both of which have a large 



tion, 1880. Allen, A Monograph of the Bats of North America, Bull. 

 U.S. Nat. Mus., No. 43, 1893. H. Winge, Chiroptera (viv. et foss.) ex 

 Lagoa Santa, Minas Gerass, Brasil., E. Museo Lundii, 2, 1, 1892. 



