146 



LOWER VERTEBRATES. 



band of scales above the lateral line and along each side of the belly become elongate, 

 closely imbricated, with the free points projecting, giving the region a villous appear- 

 ance. It is very abundant on the coasts of arctic America, both in the Atlantic and 

 Pacific, and is an important source of food to the natives of those regions. 



The surf-smelts (Hypomesus) resemble the true smelt in form and coloration, but 

 have the mouth smaller, the teeth feeble, and the ventral fins inserted further back, 

 under the middle of the dorsal. One species {Jlypomesus p>'>'etiosus) is found on the 

 Pacific coast, from Monterey to Alaska. According to Mr. James G. Swan, who has 

 published an excellent account of its habits, it has " its belly covered with a coating of 

 yellow fat, which imparts an oily appearance to water where the fish have been cleaned 

 or washed, and makes them the very perfection of pan-fish." 



The surf-smelt comes into Puget Sound in vast numbers in late spring and summer, 

 and are sometimes so abundant that "the water seems to be filled with them." They 

 cast their spawn along the shore in the fjord bays. They "come in with the flood 

 tide, and when a wave breaks on the beach, they crowd up into the very foam, and as 



Fig. 95.— Thaleichthys paciJicitSj eulaclion, caudle-lisU. 



the surf recedes, many will be seen flapping on the sand and shingle, but invariably 

 returning with the undertow to deeper water." The superstition is prevalent among 

 the Quillehute Indians of Washington Territory, that the first surf-smelts " which 

 appear must not be sold, or given away to be taken to another place, nor must they be 

 cut transversely, but split open with a mussel-shell." Tliis species never enters fresh 

 waters so far as known, but farther northward, in Alaska and Kamtschatka, a second 

 species (Ilypoiyiestis olidus) enters the streams and spawns in fresh-water ponds. 



Of all the families of fishes, the one most interesting from almost every point of 

 view is that of the Salmonid^. As now restricted it is not one of the largest fami- 

 lies, ns it comprises less than a hundred species, but in beauty, activity, gaminess, 

 quality as food, and even in size of individuals, different members of the group stand 

 easily with the first among fishes. The following are the chief external characters 

 which are common to the members of the family as here understood, the Argentinid* 

 and Salangidse, usually included with them, being here placed in separate groups: 

 Body oblong or moderately elongate, covered with cycloid scales of varying size. 

 Head naked. Mouth terminal or somewhat inferior, varying considerably among the 

 different species, those having the mouth largest usually having also the strongest 

 teeth. Maxillary provided with a supplemental bone, and forming the lateral margin 

 of the upper jaw. Pseudobranchias present. Gill rakers varying with the species. 

 Opercula complete. No barbels. Dorsal fin of moderate length, placed near the 

 middle of the length of the body. Adipose fin Well developed. Caudal fin forked. 



