ADYERTISEMEXT. 



The following memoir, liv Dr. Allen, is designed to exhibit the 

 present state of our knowledge respecting the species of Chei- 

 roptera, or bats, found in America, north of Mexico, and their 

 general geographical distribution. It is based principally on the 

 specimens in the Museum of the Smithsonian Institution, although 

 the collections of the Philadelphia Academy of Natural. Sciences 

 and of the Museum of Comparative Zoology of Cambridge have 

 also been consulted. 



JOSEPH HEXRY, 



Secretary S. I. 

 Sjmthsoxian Institution", 



Washington, April 26, 1864. 



PHILADELPHIA: 

 COLLINS, PRIJfTEE 



(ii ) 



