210 ON THE DISTRIBUTION OF FRESH-WATER FISHES 



of blood in the current ; or the inquisitive Chrosomus oreas, in his harlequin hues, 

 and the graceful Argyreus atronasus, would try to force away the pebbles and reach 

 the co%'eted store, while pairs of a scarlet Hi/j^sihpis cornutus (cerasinus) would chase 

 each other in and out, and by their superior size and activity keep up perpetual 

 commotion among the industrious party. The Gampostoma, too, of pale tints, and 

 painted fins, swimming in pairs on the bottom, would gather with ease whatever the 

 stream carried from the burrowing Ghresomus. 



It is believed that a full examination of the fish fauna of these streams will furnish 

 a good standard for the general estimation of the relations of the species of rivers 

 within the same zoological district, heading in a commou elevated region, whose 

 embouchures are most distant. In consequence of the latter condition, the greatest 

 probable diversity of species is to be anticipated, while the proximity of the head 

 waters furnishes the most probable opportunity for the commingling of the faunae, if 

 such ever can take place. 



A synopsis of the species follows, after which their relations to the topography of 

 the country, and to the general fiiuna, will be examined. 



Sect. II. — Catalogue. 



PERCIDJE. 



The genera allied to Boleosoma are represented by numerous species in the United 

 States. Prof. Agassiz has given (Amer. Jour. Sci. Arts, xvii, 305) a synopsis of the 

 genera. All of these I have not been able to distinguish as yet, and include them 

 under the following : 



I. Second dorsal equal to anal fin; vomerine teeth. 



A series of caducous ventral shields, ...... Etheostoma. 



No ventral shields ; body scaled, CoTTOGASTER. 



Muzzle obtuse conic ; osseous anal radii ; scales only in a few rows 



on the sides, Pleurolepis. 



II. Second dorsal much larger than anal fin ; vomerine teeth. 



Muzzle conic truncate; body entirely scaled ; two osseous anal radii, Percina. 

 Muzzle obtuse conic or decurved ; two bony anal radii ; body scaled, Poecilichthys. 

 Muzzle obtuse conic ; one bony anal ray; body scaled, . . . Boleosojia. 



III. Second dorsal much larger than anal fin ; vomerine teeth 

 wanting. I 



Muzzle obtuse ; two osseous anal radii ; body scaly, . . . Hyostoma. 



The genus Alvarius Girard enters probably Section II, but the vomerine teeth are 

 not described. It is characterized by an elongate slender head, and lower jaw longer 

 than the upper. 



