174! Mr Shaw's Experiments on tlie Fry of the Salmon. 



again changed to a dark colour, which gradually disappeared 

 on exposure to the light. The change of colour is produced 

 alike under a bright or cloudy sky. This singular phenome- 

 non, with which I have only now become acquainted, adds an- 

 other to the many beautiful provisions Nature has made for the 

 safety and protection of her creatures. The cause, however, is 

 a problem I make no pretensions to solve. 



To recur to the subject of the salmon's growth, I trust I 

 have now succeeded, by a process of demonstration the most 

 exact that could be attained, in establishing the fact, that the 

 young salmon does not pj-oceed to the sea the same year in which 

 it is hatched. Although I may not yet have succeeded in con- 

 vincing naturalists of the identity of the parr and the young 

 salmon, it may yet be conceded that my researches have not 

 been altogether unproductive of benefit, either in a scientific 

 or economic point of view, if I have corrected an erroneous 

 opinion as to the growth of the latter, entertained both by the 

 legislator and the naturalist. The belief that the salmon mi- 

 grates the same year it is hatched, has created an indiscrimi- 

 nate slaughter of that fish, at an age when it especially re- 

 quires the protection of the Legislature. There is no fish in 

 our rivers that takes the fly more readily, and every little tyro 

 who can cast his angle on the stream, can reckon pretty con- 

 fidently on killing eight or ten dozen per day. Where a 

 salmon river, therefore, runs through a populous country, the 

 destruction of the fry from this cause alone is incalculably great. 

 It is true the Legislature has made provision for protecting the 

 young salmon for one month, viz. during the brief period it re- 

 mains in the river after assuming the migratory dress, but for 

 the two first years of its existence it is at present entirely un- 

 protected. 



Before concluding, I may advert to the perplexing circum- 

 stance of the apparent maturity of the sexual organs of the 

 male, and the immaturity of those of the female parr. In my 

 former paper in this Journal I have stated as follows : — 



" That the female parr does not spawn is undeniable ; and although the 

 male parr of eighteen months old is to be found in the river, with the milt 

 flowing from it in abundance, all the winter round till about the end of Feb- 

 ruary, yet no instance has fallen under my observation of the roe in any fe- 

 male of the same age, or indeed of any age, having advanced to similar ma- 



