SALMON AND TROUT IN ALASKA. 19 



of pupil. In life "back grassy green, thickly spotted; a dark blotch on distal half of 

 anterior dorsal rays, posterit)r rays colorless; tips of caudal lobes dusky; lower fins 

 colorless; no trace of parr marks; iris washed mth golden" (Rutter). In alcohol the 

 dark of the back reaches the lateral line in front, then rises under dorsal to about the 

 fifth row of scales above lateral line, and on caudal peduncle approaches the line 

 to about third row of scales. Numerous round dark spots about one-third diameter 

 of pupil on back from nape to caudal, sometimes falling into about 2 irregular rows on 

 each side, with others scattered, sometimes wholly irregular and often continuing on 

 to top of head; the interspaces about twice size of spots. Dusky of dorsal includes all 

 but tips of last 3 or 4 rays; axil and inner surface of upper part of pectoral slightly 

 dusky; tip of chin and adipose fin dusky. When scales are removed, round parr marks 

 may be noted in specimens up to 200 mm. in length. 



Almost from the first free-swimming stage the sockeye may be distinguished from 

 any species except the humpback by the length, number, and fineness of the gillrakers. 

 The humpback at times exliibits a greater number of gillrakers, and these of greater 

 proportionate length, than the sockeye from the same locality. In tliis case, however, 

 the small sockeye fingerlings may be recognized by the color, and the larger by their 

 coarser scales, greater depth, and larger eye. 



The Steelhead Trout, Salmo gairdneri (Richardson). 



There are three accepted species of trout in Alaskan waters — the steelhead, rainbow, 

 and cutthroat. I have been able to find but one type of fry, and am even unable to 

 find distinguisliing marks in the young of known species grown in the hatcheries. The 

 fry here described I have called steelhead, for the reason that it is found in abundance 

 migrating to the sea from streams in which large numbers of steelheads are known to 

 spawn. The description may be taken in general as applying also to the rainbow and 

 cutthroat trout fry. 



This fry (pi. i, fig. 7), at the time of closure of the ventral walls, averages between 

 30 and 32 mm. in total length. Depth about 6; head 3.5 in body; eye 3 in head; pec- 

 toral 1.66; dorsal 2; anal 2.25; ventral 2.5. Head pointed^ greatest depth through 

 middle in front of dorsal; gillrakers very short and well separated; about 5-10 to 

 be made out by counting the faintly developed tubercles, longest about one-third 

 diameter of pupil, equal to or less than one interspace. 



General color silvery, sometimes with brassy iridescence, parr marks 9 to 12, deep 

 and narrow, usually dark and contrasting sharply with the silvery interspaces. Body, 

 except belly in front of ventrals, and fins, except the paired ones, with punctulations; 

 dorsal with front rays black; anal with posterior rays less shortened than in salmon, 

 which character with the fewer rays gives the fin a more rounded appearance 



The Charr, or Dolly Varden Trout, Salvelinus malma (Walbaum). 



The charr fry (pi. i, fig. 8) has undergone complete absorption of the yolk sac 

 at 26 mm. length. It is slender, with greatest depth through pectoral, much 

 resembling in shape and general appearance the larger sockeye of a somewhat later 

 stage. Depth about 5 in body; head 3.5; eye 3 in head; pectoral 1.5; dorsal 1.66; 

 anal 2.25; ventral 2.5; gillrakers about 4 to 7 or 8, somewhat longer in proportion than 

 in the steelhead, longest equal to about one-half eye, equal to or slightly greater than 

 an interspace. 



Of lighter general ground color than the steelhead, the parr marks occurring as 7 to 10 

 round blotches about the size of the eye, along lateral line; other similar blotches on 

 back. Lower fins immaculate. Readily distinguishable by the slim tapering shape, 

 general brownish color, size and shape of blotches, and anal fin. 



In fingerlings, about 40 mm. long, depth about 4.5, greatest between dorsal and 

 pectoral; head 3.GG; eye nearly 4 in head; pectoral 1.4, dorsal 1.6; anal and ventral 



