542 NATURAL HISTOEY OF AQUATIC ANIMALS. 



common White-fish. Its size is less than that of the White-fish. I know nothing of its com- 

 parative value as food. The stomach of one specimen examined by me contained small Limncea- 

 like shells. Nothing definite fs known of its breeding habits. 



ROCKY MOUNTAIN WHITE-FISH COREGONUS WILLIAMSONI. 



This species is usually known as the White-fish; in Utah as the "Mountain Herring." It 

 reaches a length of a little more than a foot, and a weight of about a pound. It is found through- 

 out the Rocky Mountain region, in cold, clear lakes. It is abundant in Utah Lake, Lake Tahoe, 

 and in most of the lakes of Washington, Oregon, and Idaho. It is frequent in the market of 

 Salt Lake City, and sometimes comes into the San Francisco market. It spawns in October and 

 November, running from the lakes into the small streams for this purpose. As a food-fish it ranks 

 high, being similar to its Eastern relative, C. quadrilateralis. 



THE CHIEF MOUNTAIN WHITE-FISH PEOSOPION COUESII. 



"A specimen of a White-fish was taken in Chief Mountain Lake, writes Milner, at the eastern 

 edge of the Rocky Mountains, by Dr. Elliott Coues, U. S. A., surgeon and naturalist of the 

 Northern Boundary Commission. This specimen is very different in its type of form from any 

 species hitherto described from this continent. In Giinther's arrangement of the species of Core- 

 gonus, it would be placed in group (a), with the upper jaw produced into a cutaneous appendage. 

 In this particular it resembles Coregonus o.ryrkynchus Liu. and C. Lloydii Giinth. Unlike these 

 species, it is an elongate fish, the proportion of height to length being much the same as in C. 

 WUUamsoni Gir. and G. quadrilaterals Rich.; it also resembles this tvpe of form in the narrow 

 supplementary bone of the maxillary, and the former species in the shape of the maxillary. 



"The only previous reference to a fish supposed to be of this genus, from the Saskatchewan 

 River, is in some remarks appended to the description of C. labradoricus in the "Histoire Naturelle 

 des Poissontt." Valenciennes refers, in the most undecided manner possible, to a fish which he 

 believes to be a salmonoid, and makes his diagnosis from a drawing. There is, in fact, no direct 

 evidence in what he says to prove that the specimen was in his possession. He admits that he is 

 "not able to determine with certainty the genus"; and, after stating that "my first impression 

 was to make it a Coregonus, since I have placed the design by the side of the other species of the 

 same genus," ends this most uncertain and undecided effort to determine its relationship, with the 

 question, "Could one name it Coregonus angusticeps?" 



" It may be that the specimen at hand is a fish of the species indicated in the above name, the 

 ascribed locality heightening this possibility; but there can be no consideration of the matter that 

 will decide it, and the name is consequently passed over. The character given of fifty-five scales 

 in the lateral line is very far from agreeing with Dr. Coues's specimen, and, in fact, with any 

 description of a Coregonus we have seen, and may indicate that the author was right in his hesi- 

 tancy to decide upon the genus. 



"The most marked feature is the extensive prolongation of the snout, which protrudes far 

 beyond the opening of the mouth. The head narrows regularly toward the anterior of the frontals, 

 where two strong angles are found narrowing the, head abruptly at the point where the short 

 supraorbitals join, and the frontals and nasals continue forward in a narrow, blade-like extension. 

 The supraorbitals form a hold prominence at the anterior of the orbit. The maxillary is short, 

 dilated at its posterior portion, and has a narrow supplementary bone. The premaxillaries are 

 somewhat retroverted, and have very little width, making the muzzle thin and narrow, as it is in 

 C. quadrilateralis and C. WiUiamsoni. The adipose tin is large, attached to the body almost to the 

 posterior extremity, and is ensheathed in .scales for a considerable distance from the dorsal line. 



