CARP SUCKER. 809 
opercle broad, the operculum in the adult more or less rugose; isthmus moderate; 
pharyngeal bones remarkably thin and laterally compressed, with a shallow furrow 
. along the anterior margin on the inside, and another more central one on the outline of 
the enlarged surfaces; teeth very small, compressed, nearly equally thin along the 
whole inner edge of the bone, forming a fine comb.like crest of minute serratures ; 
their cutting edge rises above the inner margin into a prominent point. Gill-rackers of 
anterior arch slender and stiff above, becoming reduced downward. Body ovate or ob- 
long, the dorsal outline more or less arched, the ventral outline more nearly straight, 
the depth from one-half to one-third the length, the sides compressed ; the back notably 
80, forming a sort of carina; caudal peduncle short and deep; scales large, about equal 
. over the body, their posterior margins slightly serrate; lateral line well developed, 
nearly straight, 34 to 41 scales; 12 to 15 scales in a cross-row from dorsal to ventrals ; 
dorsal fin beginning near the middle of the body, somewhat in advance of ventrals, fal- 
cate, its anterior rays very much elevated and usually filamentous, their height rang- 
ing from one-half to one and one-third the base of the fin, the number of developed rays 
ranging from 23 to 30; caudal fin well forked, the lobes equal; anal fin comparatively 
long and low, emarginate (in males ?), its number of developed rays usually 8; ventrals 
shortish, with usually 10 rays: pectorals short; sexual peculiarities little marked ; in 
some species, at least, the males in spring have the snout minutely tuberculated ; colora- 
tion always plain; 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 cham- 
bers. Size medium or rather large. 
ANALYSIS OF SPECIES OF CARPIODES, 
“Dorsal fin with its anterior rays shortened, one-half to three-fourths as long as the 
base of the fin. 
a. Head short, 44 to 5 in length; anterior rays of dorsal short, notably thickened 
and osseous at base. ‘ ; . CARPIO. 30. 
aa. Head medium, 3% to 44 in length ; ie rays of dorsal not thickened. 
b. Body oblong, the depth 2% in length; scales 6-37-5. . . CYPRINUS. 31. 
bb. Body short, the back arched, the depth 24 in length, scales about 8-40-6. 
THOMPSONI. 32. 
aaa, Head long, 34 in length; eye nearly median. 6 : BISON. 33. 
**Dorsal fin with its anterior rays about equal to the length of the base of the fin. 
c. Muzzle conic, projecting. . ° : ¢ : VELIFER. 34, 
ec. Muzzle very abruptly obtuse. 
d. Front margin of lower jaw notably in advance of the eye. 
CUTISANSERINUS. 35. 
dd. Front margin of lower jaw not in advance of the front margin of the eye, 
the snout being extremely blunt. 5 . : DIFFORMIS. 36. 
00 CARPIODES CARPIO (Rafinesque) Jordan. 
Big Carp Sucker; Olive Carp Sucker. 
Catostomus carpio, RAFINESQUE, Ich. Oh., 1820, 66. 
Carpiodes carpio, JORDAN, Bull. Buffalo Soc. Nat. Hist., 1877, 95 ; Man. Vert., 1876, 297; 
Proe Acad. Nat. Sci. Phila. 1877, 72; Bull. U.S. Nat. Mus, ix, 1877; Man. Vert, 
2d Ed., 1678, 321; Bull. U. S. Nat. Mus., xii, 1878, 200.—NxELson, Bull. No. 1, Ills. 
Mus. Nat. Hist., 1876, 49.— JorRDAN and COPELAND, Check List, 1876, 158.—JoRDAN 
and GILBERT, in Klippart’s Rept., 1876, 63. 
