CLASS MAMMALIA. 



Supplementary Essay on the Cheiroptera. 



According to the opinion of some clever writers the 

 quadrupedal form is the natural and primitive construction 

 of the mammiferous tribes. It appears, say they, to be best 

 suited for the reciprocal relations which subsist between 

 those animals and the various localities by which they are 

 environed. Accordingly, they consider the deviations from 

 this original plan in the light of anomalies ; and the pro- 

 gressive locomotion of man, for example, on one pair of ex- 

 tremities, while the other is adapted to different uses, and 

 fits him for new destinies, they believe an exception to the 

 general rule . 



If relatively to man this consideration be curious, how 

 much more reason have we for surprise on the contempla- 

 tion of other exceptions to this common law which also 

 seem to depart from all rules of proportion and all adapta- 

 tion of means to ends. The original plan seems utterly 

 overturned, and the combinations which result from its sub- 

 version, can scarcely be deemed less than monstrous. 



Such are the sentiments which a general xiew of the bats 

 is likely to produce in the mind of an observer. We are 

 prejudiced against their deformity, and revolted by their 

 disgusting ugliness. Such ideas, indeed, have been carried 

 so far that nations have not hesitated to pronounce these 

 animals impure, and not only to abstain from touching them 

 but even to avoid all knowledge of them whatsoever. 



The writings of naturalists sufficiently attest the early 

 ignorance respecting the peculiarities of this singular genus. 

 Aristotle defines them to be birds with membranous wings. 

 He hesitates, however, to class them with the winged tribes, 

 on account of their feet, and perceiving them unprovided 

 with four distinct feet, he cannot prevail upon himself to 



