Order X. Chiroptera. Bats. 
H. Allen, A Monograph of the Bats of North America, 1864, 2d ed. 
1893, Bull. U.S. Nat. Mus., Wash. No. 43. 
G. E. Dobson, Catalogue of the Chiroptera in the British Museum, 
1878. 
G. S. Miller, Reviston of North American Bats of the Family Ves- 
pertilionide, North American Fauna, 1897, No. 13. 
The Order CHIROPTERA contains those mammals whose structure 
has been so modified as to permit of extended aérial progression. 
The fingers are greatly elongate, and between them is spread a 
delicate sensitive membrane, extending to the legs, and this consti- 
tutes the wing. The legs are weak, but the arms are greatly devel- 
oped, while the chest muscles, lungs and heart are very capacious. 
The ribs are flat and placed close together. Bats are nearly helpless 
when upon the ground and the most skillful among them at terrestrial 
progression can only shuffle along, and they rarely alight upon the 
earth voluntarily. Odoriferous glands are found in many species, 
exuding a secretion that is very powerful and repelling, and which 
acts either as a means of protection against predatory animals, or to 
bring sexes together during the rutting season in the dark caves in 
which they usually take up their abode. In many species a mem- 
brane stretches between the hind limbs enclosing the tail, which 
enables the animals to move and turn with great rapidity, this broad, 
rudder-like contrivance acting as a lever in their flight. These bats 
are insectivorous, and belong to the Family VESPERTILIONID&, and 
with them rapid movements are necessary to enable them to pursue 
successfully the flying insects. upon which they live. Fruit-eating 
bats do not require this arrangement, as their food is stationary. 
Bats are divided into two groups, MEGACHIROPTERA and MICcROCHI- 
ROPTERA, fruit-eating and insect-eating (sometimes blood-sucking) 
bats. With the first of these groups this work has nothing to do. 
In many bats, foliaceous cutaneous expansions exist about the nos- 
trils, these often taking extraordinary shapes, and occasionally with 
erect portions of considerable height and width. These are known 
as ‘‘nose-leaf’’ bats, and their physiognomy is the most outré and 
bizarre of all the members of this Order. These apparently eccen- 
tric and useless structures are, onthe contrary, of considerable impor- 
tance to their possessors, for they are exceedingly sensitive and act 
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