354 Royal Society of Edinburgh. 



together, and seemed restlessly disposed to escape from the limits of 

 their confinement. 



Another still more confirmatory circumstance is the following. 

 It had long been noticed that the young parr of the second year was 

 a not less constant attendant upon the adult female salmon when 

 depositing her spawn than was her own mate, the milt flowing 

 abundantly from his body, and for no other apparent purpose than 

 the impregnation of the salmon's roe, — no female parr in similar 

 circumstances ever being detected. This fact led Mr. Shaw to the 

 inference, that however different the age of these two fish, yet the 

 union could arise from nothing but identity of species ; and he there- 

 fore subjected to precisely the same experiments as those above de- 

 scribed, the roe of the adult female salmon, and the milt of the tiny 

 parr. Portions of the spawn thus treated were put into the artifi- 

 cial pond No. 2. It proved to be impregnated ; the produce during 

 the first year having all the appearance of true parr : toward the 

 end of the second year they assumed their silvery hue, and in fact 

 the young fish in pond No. 2, underwent precisely the same changes 

 as those of No. 1. Nor was this a hybrid race ; for one of these of 

 the second year was again made the subject of experiment with the 

 adult female salmon, his milt being brought into contact with her 

 roe, and this new progeny appeared identical with those already 

 noticed. Specimens were exhibited to the Society of the parent 

 adult salmon, male and female, and of some of the young of the 

 ponds, killed when they had the regular markings of the parr, and 

 afterwards when they had assumed the migratory dress of the young 

 salmon. 



In the conversation which followed. Professor Christison stated 

 that, along with Mr. Shaw, he had personally examined and could 

 confirm the accuracy of every one of the author's statements, both 

 in the previous communication and the present. Mr. James Wilson 

 likewise offered some remarks, insisting particularly upon the fact 

 that the specimens before the Society demonstrated that these fish 

 had, at one period of their existence, all the genuine characters of 

 true parr, and indisputably were the parr of the naturalist and the 

 angler, and were as certainly at a subsequent period transformed 

 into the young salmon ; and Professor Traill closed the discussion 

 by avowing, that although from some anatomical details there had 

 long existed in his mind difficulties in the way of arriving at the 

 same conclusion with the author, yet he could not withstand the 

 evidence he had just heard ; that he was a convert to Mr. Shaw's 

 opinion, and that he considered his communication as one of the 



