OTPMNlDiE. — cviri. 805 



slender; moutli large, the upper jaw longest; barbel 

 well developed; fins large; head small and much flat- 

 tened above; scales large, olivaceous; si,des silvery. 

 D. I, 7; A. I, 7; lat. 1. 50. Minnesota north and west, 

 abundant; a large species of a singular form. {Pogon- 

 ichthys communis, B. & G.) 



20. CERATIDHTHYS, Baird. Hoebtt Heads. 



{N'ocomis, Girard.) 



* Mouth terminal, large ; teeth 4 — 4 (sometimes 1, 4 — 4, 1) ; size 

 large ; dorsal over ventrals. 



1. C. biguttatus, ( Kirt. ) Girard. HoEioiD Chub. 

 Jebkbe. Bluish olive, sides with bright green and 

 coppery reflections; a curved blotch behind the opercle; 

 fins pale orange, unspotted; white below, rosy in spring; 

 adult males in the spring with the top of the head very 

 much swollen, elevated into a sort of crest, sometimes 

 nearly one-third of an inch higher than the level of the 

 neck, covered with large tubercles; a stout species, with 

 large scales which are not crowded anteriorly; young 

 with a dark caudal spot; head 4 in length; depth nearly 

 the same; D. I, 8; A. I, 7; lat. 1. 40 to 45; L. 6 to 9. 

 Penn. to Utah and S. ; abundant almost every where ; the 

 most widely dijBFused of all our fresh water fishes. [C. 

 biguttatiis, (Kirt.) Bd., O. stigmaticus, cyclotis, etc.. 

 Cope.] Breeding males sometimes have a red spot on 

 each side of head, hence the specific name. 



2. C. tnicropogon. Cope. Head short, almost exactly 

 as in Luxilus cornutus^ barbel small; caudal peduncle 

 slender; teeth 4 — 4; lat. 1. 40. Conestoga R.; but one 

 specimen known — ^perhaps a hybrid. 



