124 CHEIROPTERA. 



numerous in the South of Europe, where the ruined edifices which abound 

 in Italy, Greece, and Spain, send forth whole armies. They are quite as 

 numerous occasionally in our own country. In a building in Maryland 

 nine thousand six hundred and forty bats by actual count were destroyed 

 by new tenants who entered the house after it had remained for some 

 time unoccupied. 



The scientific name given to this peculiar order of creatures is CHEI- 

 ROPTERA ; a word compounded of the Greek word clicir "a hand," and 

 ptcron "a wing," and expressive of the fact that they are mammals with 

 winged hands. 



This winged hand deserves our careful notice. hW. the fingers of the 

 hand, with the exception of the thumb, which is short, has a nail, and is 

 quite free, are immoderately long, and united by means of a transparent 

 membrane, which is without hair. This membrane covers also the arm 

 and fore-arm, and is nothing else than a prolongation of the skin of the 

 flanks. It is composed of two very thin layers, one a continuation of the 

 integuments of the back, the other that of the abdomen. It also extends 

 between the posterior limbs, where it is more or less developed, accord- 

 ing to the species, and there takes the name of the interfemoral mem- 

 brane ; but it never reaches the toes of the feet, which are short, and 

 have nails. 



It is owing to this membranous sail that Bats direct their course 

 through the air in the same manner as Birds. When they are at rest, 

 the}' fold their wings around them, enveloping their bodies as if in a 

 mantle, just as we close an umbrella. The short, free thumb takes no 

 part in extending the leathern wings, but it has to supph' the place of 

 fore-limbs when the bat is climbing or clinging. The foot has one strik- 

 ing peculiarity; it has a bone which is confined to the Cheiroptera. This 

 spur-bone springs from the heel, and serves to stretch the membrane 

 between the leg and the tail. 



The nose in all varieties of the Cheiroptera is highly organized. Not 

 merely are the nostrils well opened, and capable of being closed or dis- 

 tended by peculiar muscles, but many families have in addition most 

 extraordinary nasal appendages. 



The ear too is equally complex ; it consists of a very large cochlea, 

 which is susceptible of very easy motion. There exists too a large, 

 movable, variously formed flap, the tragus or ear-cover, which serves to 

 close the auditory canal and exclude sounds which the bat cannot endure, 



