

CHAPTER IT. 
ORDER CHIROPTERA 
THE BATS. 
This remarkable group of animals is at once the least under- 
stood and most interesting of the mammalia. The order is a 
large one, including over four hundred species which are very 
artificially arranged in from fifty to sixty genera. North 
_ America is quite poor in species as compared with the tropical 
regions of both hemispheres. The number of species in the 
sae United States does not exceed twenty, only five of which are 
as yet known to enter the limits of-our state. | 
The bats are very abruptly separated from all other animals 
; i whatever, and even the paleontological records reveal no inti- 
_ mate relationship with other mammals. The oldest known 
oy bats, remains of which have been found in the rocks, are as 
distinctly bat-like and as little like other mammals as those 
_ which now flit about upon moon-lit evenings. 
_ Bats are primarily distinguished from all other mammals by 
the possession of true wings. There are, indeed, flying squir- 
-rels, flying marsupials and flying lemurs, but in none of these 
cases is flight occasioned by true wings formed by the modifica- 
‘ _ tion of the anterior extremities. Sharing this peculiarity as 
_ they do with birds alone among vertebrates, there are vastly 
_-fewer points of similarity than of difference between the two 
groups. The wing of a bird is produced, it is true, from the 
‘ hand and arm, but in a farless perfect manner, or anatomically 
considered, at a great sacrifice of the pentadactyl plan on 
__ which the hands of most vertebrates are framed. That the less 
bee 

perfect instrument is able to effect more vigorous and longer 
sustained flight in many cases is due to other reasons, such as 
the superior lightness of the frame of birds. There are but 
two evident fingers in birds and only three are represented by 
bones. Bats commonly possess five more or less perfect digits, 
: ae four of which constitute the ribs for the support of the delicate 
pir! 

; and sensitive web which is the chief instrument of support 
