GENUS CAKPIODES. 193 



commou Carp of the Great Lakes. C. carpio is tlio most abundant spe- 

 cies in the Ohio Uivcr, where G. veli/cr and C. cutiucDincrimw^ also occur 

 in immense numbers. 



1 am convinced that neither the uutnber 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 sufficiently constant to divide the 

 species into two groups. 



Gentric Clmrackrizalions. 



Caiipiodes Rafinesqne, 1820. — " Body oblonjr, somewbat compressed ; head com- 

 pressed, nine abdominal rays, dorsal fin commonly elongate, tail equally forked." — 

 (Rai-inesque, Ich. Oh. p. 56.) 



SCLEiiOGNATHUS Storer, 1846. — " Snout slightly advanced beyouud the month ; the 

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

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

 upright branch i.s 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 cf 

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

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

 jaw is a wide, very solid bony piece, under which the uj)per 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 ojsophagus by an air-pipe." — (Stouku, 21cm. Am. Ac. Arts 

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



Cai:piodes 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 very nnich arched, 

 and regularly continuous downwards with the rather steep piofilo of ihe head. 



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

 blunt. The small mouth is entirely inferior, and surrounded by narrow thin lips, 

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

 pharyngeal bones of Carpiodcs are remarkably thin, compressed laterally, with a shal- 

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

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

 the whole inner edge of the bone, forming a fine comb-like crest of minute scrraturcs ; 

 their cutting o«.lgo 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 into long filaments. The lower fins are all pointed, 

 Bull. K M. ^0. 12—13 



