CYPRINIDA, — XXVL 51 
d. Teeth 5-5 or 4-5; dorsal inserted behind ventrals; scales very small; 
anal short. 
e. Pseudobranchiz none; lower jaw thin, with sharp, hard edge; upper 
jaw protractile, with fleshy covering; lateral line complete; body 
elongate, subterete. .. 2. 2 .:5+. . |... OXYGENEUM, 50. 
ee. Pseudobranchiz present; lips thin, normal; upper jaw protractile; 
lateral line incomplete. . . . . . . . . CHROsomuUS, 51. 
dd, Teeth 4-4; pseudobranchie present; dorsal over ventrals; scales 
rather large. 
J. First (rudimentary) ray of D. slender, firmly attached to the first de- 
veloped ray; jaws sharp-edged, the lower with a slight projection in 
front; scales before D. large (less than 15). HyBoGNnartuus, 52. 
Jf. » First (rudimentary) ray of D. well developed, bluntish, separated 
from the first developed ray, to which it is joined by membrane 
(this character never conspicuous except in adult males; often ob- 
scure in young); scales before D. small (more than 20.) 
PIMEPHALES, 53. 
cc. Alimentary canal short, less than twice length of body; teeth hooked, 
the grinding surface, if present, narrow and rudimentary; peritoneum 
usually pale ; species mostly carnivorous. 
g- Dentary bones parallel, united for their whole length (the lower jaw 
reduced to a tongue-like projection, which has a fleshy lobe on each 
side. (Fxoglossine.) 
h. Premaxillaries not protractile; upper lip thickened; scales moder- 
ate; teeth 1, 4-4, 1, without grinding surface. Exoa tossum, 54. 
gg. Dentary bones broadly arched, as usual among fishes, and united 
only at the symphysis. (Leuciscine.) 
t. Ahdomen behind V. not compressed to an edge, the scales passing 
over it; anal basis generally short (the rays 7 to 12). 
Jj. Teeth in the main row, 4-4. 
k. Maxillary without traces of barbel. 
x. [Premaxillaries protractile.] 
1. Lower lip thin or obsolete (except in one or two species), not 
developed as a fleshy lobe on each side. 
m. Mandible, interopercle, and suborbital not evidently cavernous. 
n. 1 First (rudimentary) ray of D. enlarged and bluntish, sepa- 
rated from the first developed ray by membrane (as in Pime- 
phales), this most evident in é 3 scales before D. small, 
about 28; teeth 4-4; [black blotch on front of dorsal and 
one at base of caudal always present.] . . Cxiona, 55. 
nn. First (rudimentary) ray of D. small, closely joined to the 
first developed ray; teeth 2, 1 or 0, 4-4, 2, 1 or 0; scales 
rather large; scales before D. large or small (12 to 30). 
Norropts, 56. 
mm. Mandible, interopercle, and suborbital with conspicuous 
externally visible cavernous areas (like silvery cross- 
bars); teeth 1, 4-4, 0; scales large; D. above V. 
ERICYMBA, 57. 
Wl. Lower lip developed as a fleshy lobe on each side; teeth 4—4, 
without grinding surface; D. before V.; isthmus very broad. 
PHENACOBIUS, 58. 
1 This character is more or less obscure in females and young examples. 
