352 



VELiTJCHlJATE ANIMALS. 



The < 'liriri)pti>rii, or Bat.s are essentially cliaracterised by the fact that 

 the fure-luubs are iiuieh lunger than the hind- limbs, and have 

 several of the fingers eiiornionsly elongated (fig. 256). These enor- 

 nionsly lengthened digits are united by an expanded leathery mem- 

 brane or " patagiuni," which not only stretches between the fingers, 

 but is also extended between the fore and hind lindjs, and is 

 attached to the sides of the body (fig. 257). The ])atagiura thus 

 formed often includes the tail, and is nearly or quite naked or 

 destitute of hairs on Ijoth sides. It is used as an organ of true 

 flight, and, in accordance with this, there are well-develojied collar- 

 bones (clavicles), and the breast-lione is furnished with a ridge for 

 the attachment of the iiectoral muscles. Of the fingers of the hand 



Fig. 2rj7. — Cheiroiitera. Vcsi)crtiUo discolor, one-half the natural size. 



at least three are destitute of nails. The mammary glands are 

 placed upon the chest. Teclli of three kinds are always present, 

 and the canines are always well developed. 



The Bats are all twilight-loving or nocturnal animals, and they 

 are the only Mammals which ]iossess the power of true flight, though 

 several othei'S can make extended leaps from tree to tree. The eyes 

 are small, Init the ears are very large, and their sense of touch is 

 mo.st acute. During the day they retire to caves or crevices in 

 rocks, where they suspend themselves by the hind-feet, which are 

 jirovided with curved claws. In their flight, tliough they can turn 

 with great ease, they are by no means as rapid and active as the 



