508 ZOOLOGY 



SECT. 



these support a thin fold of the integument which stretches to the 

 hind-limbs and constitutes the wing. A fold (interfemoral 

 membrane) also extends between the hind-limbs, and may or may 

 not involve the tail. The pollex is much shorter than the other 

 digits, is directed forwards, and terminates in a well developed, 

 curved claw ; in the Megachiroptera, but not in the Microchiroptera, 

 the second digit also has a claw ; the other digits are always claw- 

 less. The position of the hind-limbs is peculiar, and, in walking, the 

 knee is directed backwards, instead of forwards as in other Mammals ; 

 the five digits of the foot are all provided with claws. So com- 

 plete is the adaptation of the limbs to the purpose of flight that 

 Bats are only able to shuffle along with great difficulty on the 

 ground ; though with the aid of their claws they are able to 

 climb and to suspend themselves from branches of trees by the 

 hind -feet. In the Megachiroptera the muzzle is nearly always 

 elongated, and the pinna of the ear simple; while in the 



FIG. 1123. Bat (Synotus barbastellus). (After Vogt and Specht.) 



Microchiroptera the muzzle is short, the pinna usually compli- 

 cated by the presence of an inner lobe or tragus and often pro- 

 duced into remarkable arborescent appendages, and the nose also 

 often provided with elaborate leaf-like or arborescent lobes. The 

 surface is usually covered with soft fur, except in one group of 

 Microchiroptera in which the integument is practically naked. 

 The tail is sometimes short, sometimes well developed ; in the 

 latter case it may or may not be involved in the tail-membrane. 



In the Lemurs and their allies (Prosimii) the body is slender, 

 and the limbs adapted for an arboreal existence. The hallux is 

 divergent from the other digits of the foot and opposable to them, 

 and the same holds good, in some cases, of the pollex. In some, all 

 the digits are provided with claws, in others all but the hallux. 

 More commonly all the digits have flat nails, except the 

 second of the pes, which always has a claw. The eyes are very 

 large. The muzzle is sometimes elongated, sometimes short; the 

 nostrils are slit-like. The tail is sometimes absent or short ; more 



