Bats. 



33 



it is very doubtful whether they possess the ability. 

 For bats have none of the large auxiliary air-cells found 

 in birds, acting as a sort of reservoir, and their bones 

 are not permeated with air - cells as are those of the 

 feathered migrant. 



There are, however, several bats belonging to the 

 genus Mycteris, found in Africa, which possess a 

 somewhat similar apparatus, though not constructed 

 upon quite the same principles. 



The skin is very loosely fastened to the body, a 

 few membranous threads being the only bonds. The 

 space between this loose skin and the body is utilized 

 as an air reservoir, and is filled as follows. At the 

 bottom of the cheek-pouches on either side is found 

 a small opening, which can be closed at the will of 

 the animal, and the air prevented 

 from escaping. When the bat 

 wishes to inflate its body, it closes 

 the mouth, and forces the air from 

 the lungs through the cheek-pass- 

 ages into the vacant space. To 

 such an extent does it inflate itself, 

 that it loses all resemblance to a 

 bat, and looks merely like a round 

 ball of fur provided with head and 

 limbs. 



The objects of this curious struc-i 

 ture are not known, besides the 

 evident one of increasing the 

 buoyancy of the animal. 



The shoulder-blades of the bat 

 are enormously large, almost cover- 

 ing the whole of the ribs. These 

 also are large and strong, and the 

 breast-bone, besides being of un- 

 usual length, is furnished with a 



Keeled Breast-bone of 

 Bat. 



