SUPER-ORDER INEDUCABILIA. 



ORDER CHIROPTERA. 



The Bats have the anterior members adapted for flight ; the humerus 

 is long and slender, the ulna rudimentary, attached to the curved radius, 

 which constitutes the bulk of the forearm ; the carpus is composed of six 

 bones ; the metacarpal bones, five in number, are much elongated, as are 

 the phalanges, which are two to five in number — usually two. The 

 bones of the arm and hand support a thin, leathery skin, arising from 

 the sides of the body and extending backwards on the hind members 

 down to their tarsi, and including the tail. Tail usually of nine joints; 

 the interfemoral membrane may or may not include the tip of the tail. 

 The nervous system is highly developed, especially the special senses of 

 hearing and touch. The ears, externally and internally, are highly per- 

 fected. The auricles of the insectivorous Bats are frequently much larger 

 than the head, and of great variety of shapes, their variations in form 

 being of great importance in classification. The nose is, in many Bats, 

 the seat of extensive dermal growths, composed of reduplications of the 

 skin, which probably act conjointly with the wing-membranes to aug- 

 ment the sense of touch. The skeleton is noted for its lightness and 

 tenuity, the bones of the Little Brown Bat weighing but eleven grains. 

 The teeth vary from thirty to thirty eight, which, combined with the 

 marked differences in their contour, furnish important characters in 

 classification. The sternum is of great strength and excessive develop- 

 ment, the immense power employed in their active flight necessitating 

 the presence of strong osseous points for the attachment of muscles. The 

 whole structure is adapted to the habits of the animal. The great devel- 

 opment of the ribs, sternum, and scapula, for the attachment of muscles 

 of flight ; tne length and strength of the clavicle, and the long bones of 

 the anterior extremity fulfill an obvious purpose. The digestive appa- 

 ratus is simple, corresponding to their animal regimen. Some foreign 

 species are strictly frugivorous ; our species subsist on insects, mainly 

 the crepuscular and nocturnal kinds, as Gnats, Moths, Mosquitoes, and 

 even the heavily mailed Coleoptera. 



" The disappearance of the birds of day," says Dr. Allen, " is a signal 

 for the advent of the dusky host, which, as it were, temporarily relieve 

 from duty their more brilliant rivals in guarding the interests of ^ a- 

 ture." 

 6 



