Tfje Rainbow Troat 



By Dr. TARLETON H. BEAN, 

 Director of the New York Aquarium. 



— 



fish has a stout body, covered 

 ith moderately large scales, of which 

 there are about 135 rows between 

 the end of the head and the base of 

 the caudal fin. The head is short and deep ; the eye rather 

 large ; the upper jaw extending back almost to below the 

 hind margin of the eye. The snout is short ; the adipose fin 

 short, its width and length equal. 



There are eleven rays supporting the branchiostegal membrane ; eleven developed 

 rays in the dorsal fin besides four rudiments ; ten anal rays and three rudiments. 



COLORS. — The upper parts are greenish blue, often purplish. The sides are more 

 or less silvery and profusely spotted with small black spots, which are most numerous 

 on the upper half of the body. In the breeding season the broad crimson lateral 

 band becomes brighter and the sides of both sexes are iridescent purplish. The jaws 

 of the male are not much distorted in the breeding season, but they are very much 

 larger than in the female. 



RELATIONS. — The rainbow belongs to the group containing the brown trout of 

 Europe, the red throat of the Rocky Mountain region and Alaska, and the steelhead, 

 or Gairdner's trout, of the Pacific slope. It has been considered identical with the 

 steelhead by some authors, but wrongly so ; there is a marked difference in the young, 

 which has been observed particularly in Alaska, where the young of the two species 

 are found together, and the adults are easily distinguished. At the California State 

 Hatchery at Sisson, eggs of the two were hatched and the differences between the 

 young were plainly noted. When Dr. Jordan first saw the steelhead from Kamloops 

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