Fishes. 4797 



me by letter, that a new theory of the age of the May smolt has 

 been proposed, intended to include the history of the parr and all its 

 difficulties: it is this; "the silvery May smolt fully developed as a 

 smolt, and actually proceeding with or without the kelts, or spawned 

 fish of last autumn, is a female of one year's growth ; the males are 

 there still in the form of pans; their growth is slower ; they remain in 

 the waters another year, forming the autumn and winter parr, and 

 descending next May with their sisters of one year's growth." I do 

 not recollect a single observation directly in favour of this view, which 

 still leaves all that is extraordinary in the history of the parr unex- 

 plained. The smolts which descend the rivers in May are of all 

 sizes, from 3 inches or less to 7, 8 and 9 inches ; the males supposed 

 to be left are at least as large. These smolts are of both sexes, and 

 such will be found to be the case with those leaving the ponds on the 

 Tay. But if this be true, (which 1 doubt not), what becomes of the 

 theory ? The following are a few of the direct observations bearing 

 on this question which I find in a little work I published lately,* but 

 many more could be added to this had I leisure to examine my 

 journals. 



At my request, Mr. Harkness, of Lochmaben, fished the M, an An- 

 nan dale river, for me in December, and caught with a bait (small red 

 worms) twenty-four parr, which he transmitted to me at the time in 

 Edinburgh. Of these parr fourteen were female and ten male. The 

 largest parr measured 7 inches, the smallest 3 inches ; the average 

 was 5^ inches. The female parr were as large as the May smolts. 

 Why had they not left in the preceding May ? In the females the 

 ovaria were as usual at their minimum : in some of the males the 

 milts were of considerable size, in others not developed : they had 

 been feeding on insects. Now, if these parr were young salmon, 

 why the development of the milt in the male ? And if the females 

 belonged to the class which was to descend next May, and the 

 males only after another year, how comes it that no well-marked dis- 

 tinction can be established in respect of size ? Of the hundreds of 

 May smolts I have examined, I have never found the roe or milts 

 altered in the slightest degree ; they were uniformly at their minimum, 

 nor could I ever discover any traces indicative of a fact which 

 ought to have occurred if the winter male parr, with the milt deve- 

 loped, grew into a salmon, namely, appearances indicating that the 

 milt had been developed the preceding winter. 



* ' Fish and Fishings in the Lone Glens of Scotland. Routledge, London.' 

 XIII. 2 M 



