THE following list of families of Fishes has been prepared by Dr. 

 THEODORE GILL, at the request of the Smithsonian Institution, to serve 

 as a basis for the arrangement of the collection of Fishes of the National 

 Museum ; and, as frequent applications for such a list have been received 

 by the Institution, it has been thought advisable to publish it for more 

 extended use. In provisionally adopting this system for the purpose men- 

 tioned, the Institution is not to be considered as committed to it, nor as 

 accountable for any of the hypothetical views upon which it may be based. 



JOSEPH HENRY, 



Secretary, S. I. 

 SMITHSONIAN INSTITUTION, 



WASHINGTON, October, 1872. 



(iii) 



