6 
BULLETIN OF THE UNITED STATES FISH COMMISSION. 
reaching ventrals, the latter extending to vent in adult. Dorsal with 11 or 12 fully developed rays, 
anal with 7, the last ray in each divided to base. 
Scales more crowded and irregular in adults of this species than in C. brevirostris, the posterior 
very conspicuously larger than the anterior. This difference between the two species is less marked 
in the young. The ridges on the scales are less strong in C. stomias. 76 to 82 scales are traversed by 
the lateral line; 14 or 15 scales in an oblique series downward and backward from in front of dorsal to 
lateral line; 11 in a series vertically upward from insertion of ventrals to lateral line; 35 to 38 oblique 
series before dorsal. 
Upper portions of head and body blackish, the lower parts whitish or silvery, the two colors 
separated along a definite line traversing sides midway between lateral line and insertion of 
ventrals. Mandible, preopercle, and the contiguous part of cheeks whitish. Fins dusky. 
Abundant in Upper Klamath Lake, where all seen were spent fish in a badly mutilated and dying 
condition. 
Following is a table of measurements, the unit being hundredths of the standard length : 
Measurements. 
No. 1. 
No. 2. 
No. 3. 
Total length in mm 
Length of head 
370 
380 
220 
27* 
27* 
25 I 
Length of mandible 
11" 
12 
9 * 
Length of maxillary 
8 
8* 
6* 
Depth of head at mandibular joint 
13 
14 
12" 
1 Interorbital width 
12* 
13 
11 1 
Depth of caudal peduncle 
9* 
9 
8i 
Length of caudal peduncle 
18 
16* 
17' 
Snout to insertion of dorsal 
48 
50 
48 
Snout to insertion of ventrals 
54 
57* 
57 
7. Deltistes luxatus (Cope). 
Chasmistes luxatus Cope, American Naturalist 1879, 784, Upper Klamath Lake and tributaries; 
Proc. Ac. Nat. Sci. Phila. 1883, 149. 
Catostomus rex Kosa Smith Eigenmann, American Naturalist 1891, 667, Lost River, Oregon. 
Deltistes luxatus Alvin Seale, Proc. Cal. Ac. Sci. 1896, 269. 
The “Lost River sucker” is the most important food-fish of the Klamath Lake region. It is 
apparently resident during most of the year in the deeper waters of Upper Klamath and Tule lakes, 
running up the rivers in incredible numbers in March and April, the height of the run varying from 
year to year according to the condition of the streams. The Lost River fish are the most highly 
prized and are said to be much fatter and of finer flavor than those ascending the tributaries of Upper 
Klamath Lake. Prior to 1894 an attempt had been made to preserve the meat in cans, but apparently 
with poor success. Oil had also been extracted from heads and entrails, said to be worth from 60 to 
85 cents per gallon. 
The species most closely resembles in appearance Chasmistes fecundus, from which it differs 
principally in the simpler gillrakers, as already noted by Mr. Seale. It agrees with C. fecundus 
and differs from other species of Chasmistes in its very long, slender head, its small, nearly horizontal 
mouth, and thicker lips. When these species shall have been thoroughly investigated, C. fecundus. 
will probably be separated generically from Chasmistes. 
At the time of our visit to Upper Klamath Lake, June 13 to 16, the run of suckers was well over, 
and the only specimens observed were the dried heads on the banks of Lost River and some more or 
less diseased and mutilated individuals floating about in Upper Klamath Lake and River. One young 
specimen only could be preserved, from which the following notes are taken : 
Head 4 in length ; depth 4f. D. 12. A. 7. Lat. line 78. 
Head very long and slender, the snout and cheeks especially so, the mandibles inclined upward 
at an angle of about 35°. Snout tapering to a very slender tip, on the under side of which is the 
very small, nearly horizontal mouth, little overpassed by the premaxillaries. Premaxillary spines 
forming a decided hump on upper surface of snout near tip. Maxillary not reaching vertical from 
nostril, half length of snout. Snout 2f in head; interorbital width 2 § ; diameter of orbit (measured 
just within the bony rim) 5f. Lower lip thin, but thicker and wider than in typical Chasmistes, the 
two lobes widely separated at symphysis, which is very narrowly bordered; upper lip very narrow; 
several series of minute papilhe on each lip. Very conspicuous mucous canals on top and sides of 
