On Tivo Species of Plecottjs inhabiting the United States 

 Territory. By William Cooper. 



Read April 3, 1S37. 



Although the species which afford the type of this genus 

 or group of Cheiroptera, are sufficiently striking in their ap- 

 pearance, and are common in the populous parts of Europe, 

 it was not until the publication of the great work on Egypt 

 that they were first proposed by G. St. Hilaire as distinct from 

 the ordinary Vespertilipftes. The only ones then known were 

 two European, and one from the island of Timor. They are 

 characterised, besides what is common to them with the other 

 Bats, by the union of the base of the auricular conchs, which 

 are always remarkably ample, and sometimes enormous. Our 

 North American species, as we shall presently find, are further 

 distinguished by two large fleshy appendages in the form of 

 crests, situated between the eyes and nostrils. 



Mr. Isidore G. St. Hilaire, published in March 1832, a 

 valuable memoir on this genus, in which he enumerates eight 

 species from various and remote parts of the globe. He sub- 

 divides them into those with ears of enormous size, (in some 

 instances as long as the entire body,) and those which are 

 merely ample. In the first he places four species, of which 

 three are found in Europe, one being also common to Egypt, 

 and the fourth brought from the southern hemisphere by Peron. 

 Of those belonging to the second subdivision one is European, 

 one Asiatic, and the two others American, one being from the 

 island of Porto Rico and the other from Brazil. This last is 

 much the largest of the known species, and the VespertUio 



