536 MANUAL OF ZOOLOGY SECT. 



four ulnar digits, and these support a thin fold of the integu- 

 ment which stretches to the hind-limbs and constitutes the 

 wing. A fold also extends between the hind-limbs and may 

 or may not involve the tail. The pollex is much shorter than 

 the other digits, and is directed forwards, and terminates in a 

 a well developed curved claw ; in the Megachiroptera or 

 " Flying Foxes," but not in the Microchiroptera or Bats, 

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

 always clawless. The position of the hind-limbs is pecu- 

 liar, and the knee is directed backwards instead of forwards 



FIG. 300. Bat (Synotiis baroasrellns). (After Vogt and Specht.) 



as in other Mammals ; the five digits of the foot are all 

 provided with claws. So complete 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. 

 Amongst the Primates the body is slender in the Lemurs 

 and their allies (Prosimii), and the limbs adapted for an arbo- 

 real 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 



