THE CATFISHES 



Family III. Silurida 



BODY more or less elongate, naked or covered with bony 

 plates; head with eight barbels, the base of the longest pair formed 

 by the small or rudimentary maxillary ; margin of upper jaw 

 formed by premaxillaries alone; opercle present, subopercle absent; 

 dorsal fin short, above or in front of the ventrals ; a small fatty 

 or adipose fin back of the dorsal; front ray of dorsal and ventral 

 spinous; air-bladder large, and connected with the organ of hearing 

 by means of auditory ossicles ; lower pharyngeals separate. 



The family of catfishes is a large one, the total number of re- 

 cognized genera being more than one hundred, and the number of 

 species nearly one thousand. The majority of the species are 

 fresh-water fishes, inhabiting the rivers of warmer countries, par- 

 ticularly South America and Africa, being especially characteristic 

 of the Amazon region; only a few species are marine and 

 they are mostly tropical. The total number of species known 

 from North and Middle America is one hundred and eight, of 

 which about one-third are salt-water species belonging to the 

 genera FeJichthys, Galeichthys, Sciadeichthys, Aspistor, Selenaspis, 

 Netuma, Tachysurus and Cathorops, only the first two of which 

 have species on the United States coast. In the fresh waters and 

 on the coasts of southern Mexico, Central America, and south- 

 ward, are about a score of species of the genera Rhamdia, Pimelo- 

 della and Pimelodns, but none of them is of any importance either 

 for food or as a game-fish. 



In the United States and Mexico we have about 34 

 species, only about a dozen of which are of sufficient importance 

 to merit any consideration in the present work. Most of the 

 others are small species known as stone-cats or mad-toms, be- 

 longing to the genera Noturus and Schilbeodes, characterized by 

 the possession of a poison gland at the base of the pectoral 

 spine, and by the connection of the adipose fin with the caudal. 



Of the 30 species of fresh-water catfishes occurring in the 

 United States, all but 4 are confined to the Atlantic, Mississippi 

 Valley and Gulf States. One species (Ictalurus meridionalis ) is 

 known only from the Rio Usumacinta, in Guatemala; another 



