and on the Ova of the Salmon. 101 



many weeks, and to take its departure for the sea after this 

 brief period has elapsed. The rapidity with which the parr of 

 two years old assumes the appearance of the salmon-fry, has 

 led to this error, — the parr taking about the same time to per- 

 fect its new dress, as the young salmon is supposed to take in 

 attaining the growth at which it has arrived at the period of 

 its migration. 



As the continuance of the parr in the river for two years, as 

 well as the fact that there are always two generations in the 

 river at one time, is not generally believed, it may be necessary 

 to detail the evidence by which the truth is established. 



That this fish should not be found in the river in an earlier 

 stage than the May or summer parr, had long appeared to me 

 a very extraordinary and perplexing circumstance. I there- 

 fore made a very minute examination of the stream, where the 

 old salmon had spawned the previous winter, and I found a 

 very small but active fish in vast numbers, which I concluded 

 must be the young parr, or samlet of that season. In order to 

 prove the fact, I provided myself with a hoop, on which I 

 stitched a piece of gauze, (the fishes being too small to be 

 taken with any thing of a larger mesh,) and on the 10th 

 of May 1834 I caught two or three dozen of them. They 

 measured about 1 inch in length ; their heads were large 

 in proportion to their body, which tapered off towards the tail 

 in form of a wedge, or small pin ; and the small transverse 

 bars peculiar to the parr were very distinctly marked. I then 

 put them into two different ponds provided with a proper sup- 

 ply of running water, where they appeared to thrive remark- 

 ably well. In the succeeding May (1835), that is, after they 

 had been in my possession twelve months, I again took a few 

 of them from the pond, for the purpose of seeing what pro- 

 gress they had made. I found that they had increased in that 

 time to the length of S}^ inches, on an average, and that they 

 corresponded in every respect with the parr of the same age to 

 be found in the river, but that they did not as yet indicate in 

 the least degree the appearance of the perfect fry. Being con- 

 vinced, nevertheless, -from the result of my former experiments 

 on the parr, that they would ultimately assume a different ap- 

 pearance, I retained them in the pond, and in the second week 

 of May 1836 they had assumed (as in the former experiments) 



