FISHES OF THE KLAMATH BASIN. 
7 
head. Gillrakers short, triangular, somewhat wider than in species of Chasmistes, their free margins 
plain or moderately fringed, not bearing the dense mass of short, divided processes so conspicuously 
developed in C. fecundus and to a less degree in other species of Chasmistes. 
Scales with concentric lines and radiating ridges very strongly marked. Seventy-eight pores in 
the lateral line ; 14 scales in an oblique series from median line before dorsal downward and backward 
to lateral line; 9 scales between lateral line and base of ventrals. In 9 specimens not preserved the 
pores in lateral line were as follows : 76, 78, 78, 79, 79, 79, 79, 80, 81. Thirty-four series of scales before 
dorsal. 
Ventrals inserted about under middle of dorsal. Front of dorsal slightly nearer snout than base 
of caudal. Last dorsal ray more than half the length of the first, which is equal to distance from 
snout to preopercle. Pectorals not nearly reaching ventrals, the latter not reaching vent. Anal high, 
the anterior rays reaching rudimentary caudal rays when deflexed. Dorsal with 12 rays, the last 
one divided to base. In six other specimens counted the dorsal rays were 11, 11, 11, 11, 11, 12. Anal 
constantly with 7 rays (in eight specimens), the last divided to base. 
Very dark above, silvery on belly and lower part of sides. Dorsal and caudal dusky, the lower 
fins dusky on terminal half, light at base. 
8. Leuciscus bicolor (Girard). 
Tigoma bicolor Girard, Proc. Ac. Nat. Sci. Phila. 1856, 206. 
Gheonda cwrulea Girard, 1. c., 207. Lost River, Oregon. 
Squalius cceruleus Cope, Proc. Ac. Nat. Sci. Phila. 1883, 146. Klamath Lake. 
Abundant in Upper Klamath Lake and Lost River. A large species with compressed body, a 
tapering caudal peduncle, a small compressed head tapering to an acute snout. The snout is usually 
slender wedge-shaped, with straight outlines ; in exceptional cases blunter and heavier. The mandible 
is usually included, but projects slightly at tip in some of our specimens. The mouth is gently 
oblique, the maxillary reaching vertical from front of orbit or slightly beyond it, its length 3£ to 3i 
in head. Eye 5 to 5| in head in adults, 1| to 1* in interorbital width. Teeth 2, 4-5, 2 or 2, 5-5, 2, all 
of them comparatively small, with deeply grooved grinding surface, in adult specimens with the 
hooks obsolete. The teeth differ strikingly from those in L. lineatus, in which they are much larger, 
with strong hooks and with grinding surface convexly rounded, or in older specimens beveled by use. 
In L. intermedius they are hooked and channeled. 
Scales marked with strong concentric lines and radiating ridges, as in L. lineatus. In seven speci- 
mens examined, the scales range from 65 to 67 in the course of the lateral line, 14 or 15 in an oblique 
series running downward and backward from the median line before dorsal to the lateral line, and 30 
to 32 before dorsal (enumerating the oblique series which cross the median line). 
The dorsal fin is inserted distinctly behind the ventrals and has the upper margin straight when 
spread, slightly concave when closed. There are usually 9 developed rays, of which the first is 
unbranched, the last forked to base. In 20 specimens examined, but one had 8 dorsal rays. Anal 
with 8 rays, the first unbranched, the last forked to base; 2 out of 20 specimens examined have 9 anal 
rays. The pectorals do not nearly reach the ventrals, the ventrals usually not to vent. 
