THE CAROLINA BAT 155 



account have also developed a keel on their breast-bone. 

 The same was the case with the ancient pterodactyls, 

 and such is the case with the bat's subterranean 

 cousin, the mole, which also requires most powerful 

 muscles to move its short limbs as it does. 



The wings being thus true organs of flight, the le s 

 and tail together exercise a rudder-like action. 



Any one who has watched the flight of bats must 

 have been struck with the extremely rapid turns they 

 repeatedly make — movements necessary to enable them 

 to seize their insect food. As before said, they rarely 

 descend to the ground, but when they do so they can 

 crawl upon it, though in so doing they have a singularly 

 awkward and shuflling gait. Their wings are then closed 

 (the long filngers turned backward and lying side by side) 

 and the animal rests on its wrists and hind feet, the body 

 being dragged forward by the help of the strong hooked 

 thumb nails, which also help it to climb with ease up 

 any rough surface, even though perpendicular. 



When at rest, bats usually hang suspended, head 

 downward, by the claws of their feet, though occasion- 

 ally they turn round and hang by the claws of their 

 thumbs. 



Most nocturnal beasts have large eyes, but almost all 

 bats have very small ones. This is perhaps due to the 

 fact that bats seem in their flight to be guided by an 

 extraordinarily delicate sense of touch, as was long ago 

 experimentally demonstrated by Spallanzani. He (not 

 having any fear of anti-vivLsectionists before his eyes) 

 found that bats deprived of the power of sight, and as 

 far as possible of smell and hearing also, were still able 

 not only to avoid ordinary obtacles to their flight in 

 places quite new to them, but even to pass without con- 

 tact between threads which had purposely been extended 



