THE OREGON SPORTSMAN 35 



by reason of its larger size — one-fifth greater diameter than that 

 of Clark trout — and by a staring look which the latter has not. 

 The iris in Rainbow is broader than the Clark and of a clear, 

 pale yellow, with rarely any spots in or on the iris, while the eyes 

 of many Clark trout examined recently show the iris to be almost 

 covered by dark spots resembling the spots of the surrounding 

 skin. The narrow band of iris surrounding pupil is also of a 

 darker, rich gold. 



My opportunity for observation of Rainbow is rare, and I do 

 not venture to be dogmatic concerning him ; but I hope this pecu- 

 liar difference in size and marking of the eye may prove to be 

 distinctive. 



One other peculiarity marking the Rainbow is the usual pres- 

 ence of spots on the cheek or opercle, black and round. Color 

 and shape of these spots, as well as the peculiarity of their placing, 

 seems a distinct trait. 



SPOTS AND COLORS. 



The general color of the Rainbow, except in breeding season, 

 differs little from Clark trout, except the red bar. Sometimes 

 a Rainbow is very profusely spotted, but usually the Clark trout 

 is more numerously speckled. 



There is, I believe, a real difference in the majority of the 

 spots, in shape. I thought two years ago that in the spots was a 

 sure mark. Specimens of Rainbow then seen were marked mostly 

 by little crescent-shaped spots, sometimes joined together making 

 a "3," and with occasionally a third crescent attached to the "3"; 

 but I found some Clark trout with the same marks. However, 

 the spots of the Clark are mostly larger, and are of an irregular 

 circular or hexagonal type. The spots on base of tail are larger 

 and blacker in the Clark trout. 



The variation of spots and colors in all trout, at certain times, 

 is so great that few naturalists would risk an opinion on these 

 alone. The Rainbow frequently has red stripes under the mandi- 

 ble, but they are narrow. The Clark trout is sometimes almost 

 without these, but where present they are twice as broad as in a 

 Rainbow of the same size. Both fish return from the sea with 

 hardly a trace of this throat mark. 



