1 6 UNIVERSITY OF COLORADO STUDIES 



have been successfully introduced in several localities. Two genera of Silurids 

 are represented in Colorado. 



a. Tail entire or but slightly notched; size small to medium; adults generally less than sixteen 



inches in length Ameiurus Rafinesque 



aa. Tail deeply forked; size medium to very large Ictalurus Rafinesque 



Subfamily Ictalurinae 



Genus AMEIURUS Rafinesque 



Bullheads; Horned Pout 



Ameiurus Rafinesque, Ichthyologia Okiensis, p. 65, 1820. 



Adipose fin distinct, separate from the caudal fin; barbels eight; caudal fin 

 generally entire or but slightly notched, although in some species distinctly forked; 

 supraoccipital process pointed, separate from the interspinal buckler; small to 

 medium sized fishes. Two species of this genus, one native and one introduced, 

 are found in Colorado. 



Ameiurus melas (Rafinesque) 

 Black Bullhead, Little Pout, Horner (Fig. i) 



Silurus melas Rafinesque, Quart. Journ. Sci. Litt. Arts, London, p. 51, 1820 (Ohio River). 

 Ameiurus melas (Rafinesque) — Jordan, JBj<W. U.S. Fish Com., p. 16, i88g (Pueblo). 

 Amiurus nebulosus (LeSueur)i — Cope and Yarrow, Wheeler Survey, Vol. V, p. 640, 1875 

 (Pueblo, Arkansas River). 



Body stout and rather short, depth 3 to 4 (adult) or even 5 (young) in the 

 length to the base of the caudal; head short, broad and flattened above, widest 

 posteriorly, its greatest width about equal to the depth of the body; maxillary- 

 barbels extending to or slightly beyond the posterior margin of the head ; mouth 

 large and wide; dorsal fin higher than long; dorsal spine nearer to the tip of the 

 snout than to the base of the caudal, usually short, slightly pointed and not curved; 

 adipose fin prominent, distinctly elevated, its posterior margin free from the 

 back; caudal fin very slightly, if at all, notched; pectoral fin with a spine, which 

 is short and blunt, its length not more than 3 in the head, its posterior margin 

 slightly curved and varying from almost smooth to serrate with 6 or more small 

 teeth; tip of the pectoral fin reaching a point about midway between the origin 

 of the ventral fin and the origin of the pectoral; anal fin rather short, with 18 or 

 19 well-developed rays and 2 or 3 rudimentary rays; lateral line prominent. 



General color black, dark green or dark blue, sides with a brassy or greenish- 

 yellow luster; ventral parts yellowish or greenish gray; fins dusky, the rays 

 lighter; barbels black. 



• This reference is placed under this species since the fin formula given by Cope and Yarrow is 

 D.I,6; A.17; V.8. 



