118 COXTRIBUTIONS TO NORTH AMERICAN ICHTHYOLOGY IV. 
developed rays ranging from 23 to 30. Caudal fin well forked, tlio 
lobes equal. Anal fin comparatively long and low, emarginate (in 
males), its number of develoijed rays usually 8. Ventrals sbortisli, 
witli usually 10 rays. Pectorals short. Sexual peculiarities little 
marked ; in some species, at least, the males in spring hove the snout 
minutely tubercnlate. Coloration always i)lain ; pale olivaceous above, 
white below, but hardly silvery, the fins all partaking of the color of 
the region to which they belong. Air-bladder with two chambers. 
Size medium or rather large. This genus is very close to Ictiohus and 
BuhalicMhyn. Its species are numerous and very diflicult to determine. 
All belong to the United States. (Latin carpiodes, carp-like.) 
* Dorsal fin with the anterior rays more or less shortened, their length one-half to 
two-thirds tliat of the base of the fin; muzzle more or less conic and pro- 
jecting. 
a. Head short, 4-5 in length. 
116. C. carpio (Raf.) Jordan . — Carp Sucker. 
Head comparatively short, its length contained 4-5 times in the 
length of the body. Body more fusiform than in the others, compressed, 
but not much arched, the depth 2g-3 times in the length. Anterior 
rays of dorsal short, notably thickened and osseous at base, especially 
in the adult; the first ray nearer the end of the muzzle than the base 
of the caudal fin, the longest ray a little more than half the base of the 
fin; caudal moderately forked. Eye medium, anterior, 44 in head. 
Muzzle short, but projecting much beyond mouth. D. 30 ; Lat. 1. 36. 
Size largest of the genus. Mississippi Valley; generally abundant. 
(Cafo.s/omi/8 carpio Rafiuesque, Ichth. Oh. 1320,50; Jordan, 1. c. 200: Carpiodes num- 
mifer Cope, Proc. Amer. Phil. Soc. Phila. 1870,484.) 
aa. Head intermediate, its length contained about 4 times (3J-44) in that of body; 
anterior rays of dorsal not thickened at base. 
117. C. tiimidsas B. & G . — Carp Sucker. 
Body elongate, not much elevated ; the depth 2| in length. Head 
3^-4; the muzzle prominent, but rather bluiitish. Front scarcely con- 
cave above eyes, the profile forming a somewhat uniform curve. Eye 
small, nearly 6 in head. Anterior rays of dorsal moderately elevated, 
less than three-fourths the length of the fin ; the first ray nearly mid- 
way between snout and base of caudal. Caudal lobes blunt ; snbor- 
bitals narrow, small. Scales 6-37-5; D. 24-27; A. 8; Y. 10. Ohio to 
the Eio Grande and U^iper Missouri; common. Distinguished from 
