16 SALilOX AXD TBOUT liN ALASKA. 



bom Oregcn the longest gjllraker is about If to 2 times diameter of pupil, covering 

 3 inteE^iaces. ' 



Color silven\ dark above; top of head, back, and sides to lateral line more or less 

 thickly spott^ed with small roundish black spots about half diameter of pupil and 

 leas; distal portion of dorsal dusky, sometimes nearly black; caudal dusky; inner 

 ade of outer rays of pectoral dusky; anal and ventrals unmarked; parr marks %'isible 

 under silver. Distinguished ai sight from coho by the longer anal and the usually 

 somewhat smaller eye. but definitely by the more niunerous and finer branchioste- 

 g^ and greater number of pyloric coeca. 



The Coho Saxmox, OncorhynchuLs kisutch 0\'albaum). 



The coho fry (pi. i, fig. 6; at the time of hatching is about 27 nun. in total length, 

 the sac about 10 mm. The greater size and the peculiar shape of the yolk sac distin- 

 guidL the (X^ from the sockeye. 



These fry avostge about 35 mm. total length at closure of ventral walls. The ven- 

 tral membrane cm either side of the ventral fins is persistent for a long period. In 

 general shape the coho frj* and small fingerlings much resemble the king salmon. 

 Greatest depth just in front of dorsal, about 5 in body; thence diminishing toward 

 noee; dorsal outline arched; head about 3.75; eye 2.5 in head; pectoral 2; vertical fins 

 high, the front rays in both soon becoming extended; dorsal about 1.75; anal 2; ven- 

 tials 2.75; caudal lunation shallow. GtUrakersverj" short, little more than tubercles, 

 about 5-10. 



In Steelhead Creek, >Iay 29, migrating fry had a groimd color of smokj' green 

 with brafis>- iridescence, black punctulations everj-where except on throat and breast; 

 these pimctulations finest and most numerous on back, becoming coarser and 

 more scattered on lower side; lower side with a red overshade or iridescence; mem- 

 branes of fins with punctulations, but on pectoral and ventral these punctulations 

 onlycloee to body; remainder of these fins brownish orange; caudal-fin membranes 

 orange ground, the fine black punctulations giving a dark effect, upper and lower 

 (dorsal and ventral; margins clear brown, most pronoimced on rudimentar>' rays, 

 membrane between ray branches c-olored and dotted as between rays; membranes 

 of dorsal with very pale orange shade deepening on rear, front with black margin 

 equal in width to a central membrane, sometimes a narrow orange margin in front 

 of this; anal membranes distinctly orange with punctulations as in caudal, these 

 becoming close near margin at extremity of long rays and forming a black band about 

 equal in width to two rays and joining membrane, tips of these rays and membranes 

 white, giving the fin a white front margin and a black submargin equal to two or 

 three times the width of white; adipose with orange front and top margin; dentary 

 surface of mandible orange-ljrown at tip; maxillar\- uncolored, with scattered punctu- 

 lations; iris bronzy to brassy; cheek with bronzy ground; opercular face dark; pan- 

 marks one-third to one-fourth as wide as long, incrf^asing posteriorly in relative width 

 (antero-poeterior;, and extending about equally above and below lateral line, the 

 first partly under opercular flap, the last roundish and usually about under adipose 

 fin, the penultimate sometimes under adipose; a narrow dark median line on back; 

 smaller round spots on back sometimes alternate with parr marks. Viewed from 

 above in water, the back shows ground color bronzy, with a few scattered dark sp>ots, 

 narrow supraorbital .stripes ending at nostril, the median dark line showing distinctly 

 with bronze bands of about equal width on either side. 



In alcohol entire surface dusk>', with punctulation except on a little of breast, 

 some of thf; lower surface of head, and the paired fins. Parr marks present as 8 or 9 

 short and narrow bars, about one-half the width of the interspaces (variable but not 

 usually so broad as in the king;, and equal in length (^depthj to ah>out half depth of 

 body, lying about evenly divided by lateral line, becoming more nearly round toward 



