FOURTEKNTH ANNUAL MEETING. 69 



THE CHIEF CHARACTERISTICS OF THE NORTH 

 AMERICAN FISH FAUNA. 



BY PROF. THEODORE GILL. 



I do not think tliat I can appropriate the time which I was 

 requested to devote to a communication for your society more 

 profitably, than by inviting your attention to some of the char- 

 acteristic features of the North American fish fauna. 



If we include the marine as well as the fresh-water fishes in 

 our study, we would have to consider the constituents of four 

 primary different geographical divisions or realms, and we are 

 therefore compelled by the limits of time to restrict ourselves 

 to the consideration of the fresh-water forms alone. America, 

 north of Mexico, forms a primary terrestrio-aquatic realm 

 which has been variously designated as the North American, 

 Nearctic and Anglogaean region or realm. It is one of the very 

 richest of all in fresh-water types, considerably over six hun- 

 dred species living exclusively, or nearly so, in the rivers and 

 lakes, and these represent nearly one hundred and fifty genera 

 and about thirty-four families. It is a large exhibit compared 

 with the fauna of any of the other realms. 



If we notice the constituents of this North American fauna, 

 we find that they may be segregated into two primary categories. 

 A considerable number of the families are shared with Europ- 

 ean and Northern Asia, and many may be designated as the Arc- 

 togean, while an exceptional number of families are peculiar to 

 our continent. Those peculiar are the Amiidac, Hyodontida-, 

 Percopsidae, Amblyopsidae, Aphredoderidae, Elassomidae and 

 Centrarchidae, and several well-marked sub-families are also lim- 

 ited to the regions. Such are the Campostominae, Exoglossinae, 

 Plagopterinae, Etheostominae, Haploidinotinae and Hysterocar- 

 pinae. It is possible that even the Lepidosteidae are at present 

 peculiar, but Dr. Bleeker has named as such a species, based 

 upon a Chinese drawing of a fish supposed to have been ob- 

 tained in China. Fifteen families represented chiefly by marine 

 species, but with members also in the fresh water, are the Petro- 

 myzontids, Silurids, Clupeids, Dorosomids, Argentinids, Sal- 



