118 BULLETIN OF THE BUREAU OF FISHERIES. 
KEY TO THE FISHES OF THE SACRAMENTO BASIN. 
A. Body eel-shaped, no lower jaw. Lampreys. 
B. Supra-oral lamina with 3 teeth, the middle one large. Size large. Anadromous lamprey. 
ENTOSPHENUS TRIDENTATUS 
BB. Supra-oral lamina with a tooth at each end, none or a very small one in middle. Size small. 
Spqolol el chiaho) Ren area aca ARe nos ous snob aba cesoco Sade asosageets sacease LAMPETRA CIBARIA 
AA. Body not eel-shaped; lower jaw present. 
C. Skin smooth or covered with prickles. 
D. Dorsal and pectoral fins each with a strong spine. Catfishes............-....-.-/ \MEIURUS 
Cada tim trum caitie tows sr OUT Cl Cae een AMEIURUS NEBULOSUS 
EE. Caudal fin forked or deeply emarginate.................-...--.--...-AMEIURUS CATUS 
DD. Pectoral fin without spines, 
Fi. Ventral raysit4: 2c.n222 cf eek 2 Selo eae ees oe ee Oar ae oe eee Corrus 
Ge Ska) emtireliyy tas erate Sea cee ayer tte  ee arrte eane te ee ele erer e Corrus ASPER 
GG. Skin smooth except for a patch of prickles behind pectorals......-. Corrus GULOSUS 
GGG. Skin entirely smooth. 
H. Eye large, .3 of head 
HH. Eye smaller, less than .3 of head 
Pum. Ventral ray siiees 255. ee base ete eee ee ere ee eee ee 
CC. Sides crossed by a few vertical bony plates...........-...-.--- GASTEROSTEUS CATAPHRACTUS 
CCC. Body scaly. 
I, No teeth in mouth. 
J. Lips very large and covered with coarse papillee. Suckers. 
K. Edges of jaws with hard cartilaginous sheaths; a notch at corner of mouth 
between upper and lower lips. ........--..-.-.---- PANTOSTEUS LAHONTAN 
Ke Mouthvandalipsmot asia DOvere ees eee eee tae eee CarostoMUS 
L. Fontanelle almost obliterated in specimens 6 inches long 
CATOSTOMUS MICROPS 
LL. Fontanelle large. 
M. Dorsal with 10 or 11 rays; scales small, 80 to 95 in lateral line 
CaTOSTOMUS TAHOENSIS 
MM. Dorsal with 12 to 14 rays, scales larger, 60 to 80 in lateral line 
CATOSTOMUS OCCIDENTALIS 
JJ. Lips not large nor papillose. 
N. Anal fin short (in species here considered), with fewer than 15 
rays. Minnows. 
O. Dorsal with a serrated spine.-...-.....------------- CYPRINUS CARPIO 
OO. Dorsal without spine. Native minnows. 
P. Scales very fine, over 100 in lateral line. ORTHODON MICROLEPIDOTUS 
PP. Fewer than 100 scales in lateral line. 
Q. Upper lip with a frenum........- MyYLOPHARODON CONOCEPHALUS 
QQ. Upper lip without frenum. 
R. Mouth large, maxillary extending to below eye; large pike- 
like sfishessssces- ceo saetoeaaeeee eee PrycCHOCHEILUS GRANDIS 
RR. Mouth small, body more or less compressed. 
S. Pharyngeal teeth in two rows......--.-.----.-.--- Leuciscus 
T. Tail very deep. 
U. Anal with 8 or 9 rays, tail much compressed 
LEUCISCUS CRASSICAUDA 
UU. Anal with 10 or 11 rays, tail not so much compressed 
LEUCISCUS CONFORMIS 
