228 The Scottish Naturalist. 



In regard to the early history of the salmon- trout, little 

 appears to have been done in this country since the experiments 

 of Mr. Shaw, of Drumlanrig, so well known in connection with 

 the development of the salmon, who, in a paper read before the 

 Royal Society of Edinburgh in 1843, detailed the various phases 

 in the growth of this fish. He procured the ova and milt by shoot- 

 ing a pair of adult salmon-trout in the act of spawning in the river 

 Nith, and after fertilization placed the eggs in an apparatus and 

 hatched them. The young fish he afterwards reared to the 

 parr-stage (first year), and then tD that of the "orange" or 

 "yellow fins " (second year). As in the salmon, he found the 

 young males at the age of 18 months and upwards with the milt 

 fully developed. The young salmon-trout at this stage bear a 

 close resemblance to the common river-trout. At the age of 

 two years, and when about 7 ^-inches long, many assume the 

 migratory dress of silvery scales. Mr. Shaw observes that their 

 characters in this condition are : — " Dark brown on the back, 

 passing gradually into a white silvery appearance on the sides 

 and belly ; the pectoral fins are white, with the extremities (}i) 

 orange ; ventral fins pure white ; anal fin white, with a faint 

 dusky mark on each side ; dorsal fin light-brown, inclining to 

 black at the extreme points of the anterior rays, which are tip- 

 ped with a very little white ; posterior rays have a faint tinge of 

 orange, and the whole fin is much spotted ; adipose fin dark- 

 brown margined with red ; caudal rays of a light colour near the 

 base, running into a dark orange, terminated by a faintly-marked 

 double margin of black. The spots on the back and sides vary 

 much, prevailing principally along the back, with a few below 

 the lateral line. Each spot is surrounded by a circle of a lighter 

 colour than the general surface of the body, and this appears to 

 be a prevailing character of the trout-species, and one which the 

 sea-trout fry exhibits even after having assumed the migratory 

 dress, when every other feature of resemblance to the common 

 trout has disappeared." One of the most important points 

 noticed by this careful observer was that "a certain number of 

 the individuals of both sexes (probably about one-fourth of 

 each brood) never assume the silvery exterior, or migratory 

 dress ; and even if those which have assumed that appearance be 

 detained in fresh water for a month or two, they will re-assume 

 the dusky coating ; and the ensuing autumn both sexes have 



