VERTEBRATE ZOOLOGY. 459 



cording to his views, 32 families and 157 genera. "The 

 classification, as regards the families and higher groups, is 

 throughout that of Professor Gill;" but "the order of the 

 forms has been reversed, beginning with the most general- 

 ized forms," and ending with those " higher, or more special- 

 ized." The peculiarities of the North American fauna, from 

 an ichthyological point of view, are so great and yet so little 

 known, that a resume of its characteristics must interest even 

 the general reader. (1) No less than eight families are con- 

 lined, so far as yet known, to North America, this side of 

 Mexico ; these are the Amiids, Hyodontids, Percopsids, Am- 

 blyopsids (including the blind fish of the Mammoth Cave), 

 Aphredoderids, Elassomids, Centrarchids ( sunfishes, black 

 basses, etc.), and Etheostomids ; the last two, and especially 

 the Centrarchids, are very characteristic, and form one of the 

 most prominent features of our fauna. Of the eight families, 

 one (the Amiids) w T as formerly widely diffused in the north- 

 ern hemisphere, and may possibly be still existent in tem- 

 perate Eastern Asia. (2) In that part of Asia there are rep- 

 resentatives of three other families, otherwise peculiar to 

 North America, the Polyodontids (paddle-nose sturgeons), 

 Lepidosteids (gar-pikes), and Catastomids (suckers); of these 

 the Lepidosteids were formerly also existent in Europe dur- 

 ing the Tertiary epoch. The peculiarities of the North Amer- 

 ican ichthyic fauna are thus partly autochthonic and partly 

 due to the survival of ancient forms once widely diffused, 

 but now extinct, or nearly so, save in America. (3) Another 

 element for the southwestern fish-fauna is furnished by the 

 families of Characinids and Cichlids, both of which send rep- 

 resentatives into the adjoining United States ; these families 

 are especially interesting as being confined to Africa and 

 America. (4) Eight families are characteristic of the north- 

 ern hemisphere ; three of these (Esocids, Umbrids, and Per- 

 cids, typical perches and their allies) are special fresh-water 

 types ; the other five (Acipenserids, Salmonids, Labracids, 

 Cottids, and Gasterosteids) are almost indifferently salt- or 

 fresh-water forms i. e., they inhabit both, or are anadromous; 

 but some species are limited to the fresh water, while closely 

 related species may be marine or anadromous. (5) Eleven 

 families are cosmopolitan or common to more than two re- 

 gions ; eight of these are really marine types, and the fresh- 



