170 



that's it ; 



the elongated fingers of the fore I 

 legs 14 ; the term cheiroptera is 

 derived from two Greek words, 

 meaning wing-handed. The wings 

 of bats, or " flitter-mice," differ 

 materially from those of birds, 

 consisting of a remarkably thin 

 membrane 14, stretched over and 

 between the limbs, to which the 

 bones lo, act as stretchers, like 

 the whale-bone ribs in an um- 

 brella ; the tail, in some species, 

 being thus covered also. The 

 bones of the fingers 15, are very 



502. 



slender, and of extraordinary 

 length, diverging from each other 

 as they proceed. The thumb 16, 

 is free, and forms a kind of hook 

 by which the bats assist their 

 progression when searching for 

 insects in the crevices of walls, 

 and the bark of trees. Their 

 toes are provided with sharp 

 hooked claws, by which they 

 suspend themselves while resting 

 or sleeping. 



In the bat, the senses of smell 

 and hearing are wonderfully acute. 

 In some species, with a view to 

 the higher development of these 

 senses, the nose is furnished with 

 an extended membrane, 17, of most 

 delicate structure ; while the ex- 

 ternal membraneous ears 18, are 

 large, expanded, and capable of 

 being folded. The external ap- 



pendages of the head are abun- 

 dantly supplied with sensitive 

 nerves, so exquisite in their 

 feeling, that even if the eyes of 



the bat are destroyed, it can 

 pursue its course about a room 

 with a thousand obstacles in the 

 way, and avoid them all. Bats 

 are for the most part insect eaters ; 

 but some are fond of fruit, while 

 others are blood-suckers. 



The insectivora, or insect eaters, 

 comprise hedge-hogs, shrews, moles, 



19 



504. 



&c. To this sub-order the des • 

 man, or musk rat, 19, belongs. 

 It possesses a long and flexible 

 snout, 20, by which it feels for 

 worms, leeches, and 1 

 the larvae of insects. 

 It is a creature of 

 aquatic habits, and is *J 

 provided with broad 505. 

 membraneous feet, 1, adapted for 

 burrowing and for swimming. 



