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purposes, and are seen to associate with the female adult salmon. 

 A characteristic example of this stage was taken from the pond 

 on the 14th November 1838, being then eighteen months old, 

 and at that age all the males of the different broods exhibited a 

 matured sexual character in relation to the milt, but none of the 

 females of the same age shewed any signs of roe. Those in the 

 bed of the river manifested the corresponding character of each 

 sex, — that is, of maturity in the male, of immaturity in the female. 



The great constitutional change which converts an old parr into 

 a young salmon, usually takes place in the month of April of the 

 second ensuing year. Specimens taken from the pond on the 5th 

 of January 1839 measured six inches in length, and were twenty 

 months old. They exhibited all tlie ordinary characters of the 

 parx, commonly so called. But such as were allowed to survive 

 till the 24th May, although they gained only half an inch iu 

 length, cast off the livery of the parr, and assumed that of the sal- 

 mon, — this change consisting chiefly in the following particulars : the 

 black opercular spots disappeared, the almost colourless pectoral fins 

 became suffused with an inky hue at their extremities, the broad 

 perpendicular bars or blotches on the sides were eflFaced, and the 

 prevailing hues of dusky brown and yellowish-white were con- 

 verted into deep bluish-black above, and into silvery white below. 

 Various other specimens exhibited by Mr Shaw exemplify a simi- 

 lar change, and some of these distinctly shew, as it were, the in- 

 termediate or transitionary state between the parr and salmon. 

 The whole, however, belonged to broods which, as formerly ex- 

 plained by the author, were the original produce of adult salmon. 



The observations hitherto reported were made in confirmation 

 and continuance of those formerly laid before the Society by the 

 same author. But the circumstance of the male parrs in a state of 

 sexual maturity being found to accompany the female adult salmon 

 while she deposits her ova in the river, suggested the idea of the 

 following singular and successful experiment. • In the month of 

 January 1837, Mr Shaw took a female salmon weighing 14 lb. 

 from the natural spawning bed, from whence he also took a male 

 parr weighing one ounce and a half. With the milt of the latter he 

 impregnated the ova of the former, and placing the spawn in the 

 stream of his pond he watched its development, as he had thiit of 

 the salmon spawn fecundated in the ordinary way, and found the 

 batching and subsequent growth in all respects to correspond. 



