Chap. I.] 



BATS. 



15 



which essentially distinguishes them from the feathery 

 wings of a bird, and vindicates ' the appropriateness of 

 the term Cheiro-ptera l , or " winged hands/' by which 

 the bats are designated. Over the entire surface of the 

 thin membrane of which they are formed, sentient nerves 

 of the utmost delicacy are distributed, by means of which 

 the animal is enabled during the darkness to direct its 

 motions with security, avoiding objects against contact 

 with which at such times its eyes and other senses 

 would be insufficient to protect it. 2 Spallanzani ascer- 

 tained the perfection of this faculty by a series of cruel 

 experiments, by which he demonstrated that bats, even 

 after their eyes had been destroyed, and their external 

 organs of smell and hearing obliterated, were still 

 enabled to direct their flight with unhesitating con- 

 fidence, avoiding even threads suspended to intercept 

 them. But after ascertaining the fact, Spallanzani was 

 slow to arrive at its origin ; and ascribed the surprising 

 power to the existence of some sixth supplementary 

 sense, the enjoyment of which was withheld from other 

 animals. Cuvier, however, dissipated the obscurity by 

 showing the seat of this extraordinary endowment to 

 be in the wings, the superficies of which retains the 

 exquisite sensitiveness to touch that is inherent in 

 the palms of the human hand and the extremities of the 

 fingers, as well as in the feet of some of the mammalia. 3 

 The face and head of the Pteropus are covered with 

 brownish-grey hairs, the neck and chest are dark ferru- 

 ginous grey, and the rest of the body brown, inclining 

 to black. 



1 xeip, the " hand," and irTepbu, 3 See article on Cheiroptera, in 

 a "wing." Todd's Cyclopaedia of Anatomy 



2 See Bell On the Rand, ch. iii. and Physiology, vol. i. p 4 599. 

 p. 70. 



