36 FISH-CULTURAL ASSOCIATION. 
the surface at the same time, form a large part of the food of such 
predaceous species as do come to the surface. 
4. Coregonus nelsontz Bean. Hump-back white-fish. Bean, Proc. U.S. 
Nat. Mus., VII., 1884, p. 48. 
Known from Alaska only, occurring from the Bristol Bay region 
northward to the extremity of the territory. 
This species which was until recently undescribed, has long 
been known from Alaska, but it has been confounded with a 
Siberian species, C. syrok, from which it is really very different. 
The Russian name of the species is “Xoraéati.”” The Tinneh 
tribes of the Yukon call it “Kolokih.”” Mr. Dall, in the report of 
the Commissioner of Agriculture for 1870, p. 386, speaks of it 
as a common species characterized by the strongly arched back 
and broad tail. He says it is rather bony and inferior in flavor, 
and that it is generally used for dog food, except in times of 
scarcity. 
This species is related to C. clupetformis and C. labradoricus, 
From clupetformis it may readily be distinguished by its greatly 
arched and much compressed back. The body is oblong and 
compressed; the head is one-fifth as long as the fish without the 
caudal; the maxilla extends to the front margin of the eye and 
is about one-fourth as long as the head; the gill-rakers are only 
moderately long, the longest a little more than one-half length 
of eye, and their number is about twenty-six. The greatest 
height of the body is a little more than one-fourth of the total 
~ length in the typical example, which is about fourteen and one- 
half inches long to caudal base. The adipose fin is large and 
scaled for nearly half its height. The ventrals area little nearer 
the tip of the snout than to the root of the caudal. They are 
about as long as the head without the snout; D. 12; A. 12; scales 
1o—88—10. The type of the species is No. 29,903, taken at Nul- 
ato, Alaska, by Mr. E. W. Nelson, to whom the species is dedi- 
cated in recognition of his important zoological researches in 
that territory. 
5. Coregonus quadrilateral’s Richardson. Round white fish. (?) Krug 
(Russian). Shad Waiter; Round-fish. 
Lakes of New England Upper Great lakes; Slave Lake; Kodiak; 
Yukon River; rivers of Arctic North America. (Gunther). 
