1899.] NATURAL SCIENCES OF PHILADELPHIA. 325 



iViid yet it is fair to state that the total number of valid species 

 known to-day from Cape Horn to the equator does not exceed 300, 

 and of these only 100, more or less, are found between the equator 

 and the Tropic of Capricorn. In contrast to this we recognize 

 over 300 species along the west coast of Mexico and Central 

 America alone, from Panama to the Tropic of Cancer. 



It is certain that the southern region is fully as rich as the 

 northern, and the field — at least of Peru — remains practically 

 unexplored. Very nearly all the material that has been collected 

 has been obtained from one source — the fish-markets. The tide- 

 pools are untouched, the deep-sea fishes almost unknown, and a 

 multitude of forms, of little importance economically but of great 

 interest scientifically, await the word of the investigator to introduce 

 them to the world. 



The basis of the pi'esent paper has been a collection of marine 

 fishes made in Callao by Rear- Admiral L. A. Beardslee, U. S. N., 

 retired, on a cruise of U. S. S. " Philadelphia," during the 

 month of January, 1896. Though rather small, the coUection 

 contains a great deal of interesting material. 



The scattered condition of the literature has hindered a study of 

 the subject, and one of the principal purposes of the present brief 

 paper has been to collect and modernize the synonymy of the species 

 inhabiting this region. 



We have included all the marine species known to us, inhabiting 

 a range from Pecasmayu bay on the north to Iquique on the 

 south, and limited in a general way by the political boundaries of 

 Peru. The detailed synonymy has been given for all references to 

 the west coast of South America, and the author responsible for 

 the present generic and specific name of each form has been cited, 

 but otherwise only enough synonymy has been included to guide 

 the reader to other,' sources. The page references to Cope and 

 Steindachner are those of the reprints containing their descrip- 

 tions. 



The habitats given to many species by early workers were very 

 general, and many ranges that we have copied from their descrip- 

 tions will doubtless have to be restricted. A few species have been 

 described from ' * the west coast of South America, ' ' and have been 

 admitted provisionally into the present list until future investiga- 

 tion shall have established their true position. 



