THE VAMPIRE BAT. 115 



process, the bones which thus constitute the arm and hand are marvellously elongated, 

 becoming longer the farther they recede from the body. 



The two bones of the fore-arm are extremely long, and the bone which is 

 scientifically known by the name of the "ulna" is extremely small, and in many species 

 almost wholly wanting. The reason for this arrangement is, that the great object of 

 these two bones is, by the mode in which they are jointed to each other, to permit the 

 arm to rotate with that movement which is easily shown by the simple process of turn- 

 ing the hand with its palm upwards. This latitude of motion would not only be useless to 

 the Bats, but absolutely injurious, as the wing-membranes would not be able to be at the 

 air with the steady strokes which are needful for maintaining flight. Therefore the 

 arm is rendered incapable of rotation. 



Passing onwards from the arms to the hands, the finger-bones are strangely dispropor- 

 tioned to the remainder of the body, the middle finger being considerably longer than the 

 head and body together. The thumb is very much shorter than any of the fingers, and 

 furnished with a sharp and curve claw. By means of this claw, the bat is enabled to 

 proceed along a level surface, and to attach itself to any object that maybe convenient. 

 In some of the bats the thumb is much longer than that which is here figured. 



The bones of the breast and the neighboring parts are also formed in a peculiar 

 manner, being intended to support the broad surface of the wing-membrane, and to en- 



SKELETON OF VAMPIRE BAT. 



able it to beat the air with sufficient force. The collar-bones are long, considerably 

 arched, and strongly jointed, to the breast-bone and the shoulder-blades. In the insect- 

 eating Bats, these bones are more developed than in the fruit-eaters ; probably because 

 the former need a better apparatus for the capture of their quick-winged prey, than the 

 latter for seeking their vegetable food. Some species of Bat present a collar-bone which 

 is half the length of the elongated upper arm. 



The breast- bone is very long, and is widely expanded so as to form a strong point of 

 attachment for the two collar-bones. There is also a bony crest running down its centre, 

 which serves as a support for the enormous breast-muscles that work the wings. The 

 ribs are long and well rounded, and, indeed, seem to be much greater in proportionate 

 length than those of any other mammal. 



The lower portions of the body and limbs are singularly small in proportion to the 

 upper limbs. The legs are short and slender, and so arranged that the feet are rather 

 turned outward, for the purpose of using their sharp claws freely. A kind of slender and 

 spur-like bone is seen to proceed from the heel of each foot. When the skeleton is 

 clothed with its softer textures, these curious bones run between the double membrane 

 that joins the legs to the tail, and reach nearly half-way to the latter member. The 



