KEY TO GENERA.——CYPRINID AS. 41 
Family: Cyprinipa; (The Minnows). 
Key to Genera. 
I. (Dorsal fin long, with 2 or 3 spines, and 18 or 20rays ; introduced species. 
A. ‘Teeth in 3 rows, I, I, 3-3.1, 1, all molar; 4 barbels.— CYPRINUS. 
AA. Teeth in 1 row, 4-4, molar, but compressed ; barbels wanting.— CARASSIUS.) 
II. Dorsal fin short, without developed spine. 
A. Air bladder surrounded by many convolutions of the very long alimentary 
canal.— CAMPOSTOMA. 
AA. Air bladder above the alimentary canal, not surrounded by convolutions of the 
intestine. 
B. Alimentary canal more than twice the length of body; teeth in 1 row? 
peritoneum usually black. 
Cc: Teeth 5-5 or 4-5; scales minute.— CHROSOMUS. 
CC. Teeth 4-4; scales larger. 
D. A small barbel present at base of maxillary ; color silvery.— 
HYBOGNATHUS. 
DD. Barbel wanting; color olivaceous, little silvery —PIMEPHALES. 
BB. Alimentary canal less than twice the length of body; peritoneum usually 
silvery. 
KE. Lower jaw normally formed, dentary bones free from each other 
except at the symphysis. 
F. ‘Teeth in main row 5-5 or 4-5. 
G. Abdomen rounded behind ventral fins, not compressed 
into a scaleless ridge; anal basis short. 
H. A minute barbel present on maxillary at a little 
distance above its base.— SEMOTILUS. 
HH. Maxillary without barbel. 
I. Teeth in 2 rows, 2, 4-5, 2.— LEUCISCUS. 
Il. Teethintrow,5-5. Mouth extremely small.— 
OPSOPGODUS. 
GG. Abdomen compressed behind ventral fins into a sharp, 
scaleless ridge; anal basis longer.— ABRAMIS. 
FF. Teeth in main row 4-4. 
J. Maxillary without barbel. 
Kk. No cavernous lymph spaces visible in mandible, 
sub-opercle and inter-opercle. 
ity First (rudimentary) ray of dorsal detached 
from the first developed ray and connected 
to it by a membrane; a conspicuous black 
spot at base of caudal and dorsal —CLIOLA. 
LL. First (rudimentary) ray closely attached to 
first developed ray.— NOTROPIS. 
KK. Mandible, sub-opercle and inter-opercle, with con- 
spicuous, externally visible, cavernous lymph 
chambers.— ERICYMBA. 
JJ. Maxillary barbel present. 
M. Premaxillaries not protractile, connected to skin of 
forehead in the median line without a cross 
groove; teeth 2, 4-4, 2. RHINICHTHYS. 
MM. Premaxillaries protractile, a cross groove separat- 
ing them from the skin of forehead in front; only 
1 tooth in lesser row.— HYBOPSIS. 
EE. Lower jaw singularly formed, the dentary bones parallel and united 
for their entire length ; a conspicuous, fleshy lobe on each side at 
base.— EXOGLOSSUM. 
