GENUS CAEnODES. 193 



common Carp of the Great Lakes. C. carplo is the most abundant spe- 

 cies in the Ohio Eiver, where G. velifcr and G. cutkanncrmus also occur 

 in immense numbers. 



1 am convinced that neither the number of scales nor the number of 

 fin-rays can be relied on to distinguish species in this genus, the entire 

 range of variation being probably found in every species. The height 

 of the anterior rays of the dorsal, although subject to considerable varia- 

 tion with age and wear, seems to be sulBciently constant to divide the 

 species into two groups. 



Generic Characterizations. 



CArtPiODKS Rafinesqne, 1820. — " Body oblon<T, somewhat compressed ; head com- 

 pressed, nine a,bdomiual rays, dorsal fiu commonly elongate, tail equally forked." — 

 (Eatine-sque, Ich. Oh. p. .56.) 



ScLF.rtOGXATHUS Storer, 1846. — " Snout slightly advanced beyound the mouth ; the 

 extremity of the mouth is supported, as in the Catostomi, by the intermaxillary, which 

 is furnished in front with a well developed, isrojecting, cartilaginous ethmoid. The 

 upright branch is long, and of a styloid form, while the horizontal is shortened, and is 

 a mere keel, the inferior edge of which serves merely to support the superior angle of 

 the mouth. The remainder of the maxillary arch is formed by a fibrous ligament cov- 

 ered by a thin, undilated lip, reduced to a thin and fleshy protuberance. The upper 

 j.iw is a wide, very solid bony piece, under which the upper lip is partly drawn ; this 

 bone is concealed by the first two suborbitals, being wider and no less advanced than 

 those of the Catostomi. As to its lips, it is a Leuciscus; but the osteology of its mouth 

 resembles that of the Catostomi. The dorsal is long, like that of the Carps. The head 

 is naked, marked by lines of mucous pores. Pharyngeal teeth comb-like, finer and 

 more equal than those of the Catostomi. The air-bladder is divided into two large 

 lobes; the anterior is large and rounded, with a slight depression at its superior face ; 

 the second conical, twice* as long as the first and followed by two small lobes ; the sec- 

 ond communicates with the oesophagus by an air-pixie." — (Storer, Mem. Am. Ac. Arts 

 and Sc. 1846, p. 427 ; essentially a translation from Valenciennes's account.) 



Carpiodes Agassiz, 1855. — " The body is very high and strongly compressed, the 

 narrow ridge on the back forming the outline in front of the dorsal is vrry much arched, 

 and regularly continuous downwards with the rather steep profile of iho head. 



"The head is short, its height and length diller but little. The snout is short and 

 bluut. The small mouth is entirely iuferior, and surrounded by narrow thin lips, 

 which are more or less transversely folded. The lower jaw is short aud broad. The 

 pharyngeal boues of Carpiodes are remarkably thin, compressed laterally, with a shal- 

 low furrow along the anterior margin on the side, and auother more central one on the 

 outline of the arched surfaces ; the teeth are very small, compressed, equally thin along 

 the whole inner edge of the bone, forming a fine comb-like Crest of minute serraturcs; 

 their cutting edge rises above the inner margin into a prominent point. 



"The anterior lobe of the long dorsal is slender, its third and fourth rays being pro- 

 longed beyond the following ones iuto long filaments. The lower fins are all pointed, 

 Bull. K M. No. 12—13 



