PROCEEDINGS 



UNITED STATES NATIONAL MUSEUM 



FOU XHE] YJEAK 1893. 



Volume XVI. 



INTRODUCTION TO A MONOGRAPH OF THE NORTH AMERICAN 



BATS.* 



BY 



Harrison Allen, M. D. 



The bats constitute the order Cheiroptera. Unlike related groups 

 which are equally extensive, the bats do not vary in sufficient degree 

 to be confounded by any possibility Avith other creatures. By an un- 

 trained observer shrews might be mistaken for mice or voles, some of 

 the smaller marsupials for minks or weasels, conies for marmots. But 

 the popular impression of a bat is accurate, since this creature is the 

 only mammal adapted for true flight, and no other mammal resembles 

 it. If any mammals exist or have existed that are half bats and halt 

 moles, half bats and half lemurs, half bats and half marmots, they are 

 quite unknown to the naturalist. Paleontology is silent as to the 

 origin of the bats, though comparison of their bony framework with 

 those of the Insectivora, Lemuroidea, and Eodentia suggest that they 

 may have arisen from the mammalian stem not far from the points at 

 which the differentiation of these branches began. 



MEMBRANES. 



Let us examine the undissected bat, and endeavor to establish thereby 

 general conceptions of the creature and of some of tlie signs of the 

 superficies by which its varieties can be named. It is at once seen 

 that the anterior extremities are furnished with greatly elongated 

 fingers, the intervals between wliicli are occupied by two layers of skin. 

 Goldsmith uses a happy jDhrase when he says " the fingers serve like 

 masts that keep the canvas of a sail spread and regulate its motions." 



* The monograijli from which this introduction has been extracted will be pub- 

 lished as a Bulletin of the National Museuna. The printing of the latter having been 

 unavoidably delayed, it has beeu thought best to publish this introduction in 

 advance. — F W T 



Proceedings National Museum, VoL XVI— No. 919. 1 



Proc N M. 93 1 



