1864.] DAVY ON THE SALMONID^. 451 



growth of the sea trout in the sea is slow in comparison with that 

 of the salmon ; it is not uncommon to find food in the stomach of 

 the former when in fresh-water, but it is rare that any food is found 

 in the stomach of the latter after leaving the sea. The sea-trout, as is 

 well known to the experienced angler, is more readily taken, using the 

 artificial fly,under circumstances of weather differing from those most 

 favorable to the capture of the salmon ; a dark windy day being 

 best for the latter, a warm cloudy day with gleams of sunshine for 

 the former. One quality they have in common with river and 

 lake trouts,— that their ova are capable of being hatched only in fresh 

 and well-aerated water, leading to the conclusion that the migratory 

 species must always have been migratory, unless indeed we sup- 

 pose that there was a time when the seas were less salt than at pres- 

 ent and the lakes and rivers less fresh, and that then the habits 

 of the salmonidge were formed, and they gradually became divided 

 into the migratory and non-migratory species. 



Sir W. Jardine offered some observations on Dr. Davy's paper. 

 In reference to the male parr or young salmon being endowed with 

 the power of impregnating the ova of the adult fish, he said the 

 same power had not been found in any other of the salmon species. 

 He was not aware that experiments had ever been made with any 

 other variety, the fish not having been found in a state fit for the 

 purpose. With regard to the salmon breeding yearly, or in alter- 

 nate years, that was a very difficult point to prove ; but, as Dr. Davy 

 had observed, the number of barren fish occasionally taken, was 

 presumptive of their breeding in alternate years. If Dr. Davy 

 would go to the river Tweed in the end of November, and fish with 

 salmon roe (which was now forbidden), he might kill a basketful 

 of the Salmon eriox all in a fit condition for the table. Last year 

 he (Sir W. Jardine) went there to try experiments, believing that 

 the fence-time was far too protracted, and that the salmon kind 

 should not be taken so late in the year as November. They netted 

 the river, and in three draughts took out between seventy and 

 eighty salmon and bull-trout, not one of which was fit for the 

 table. Nothing was fit for the table except the small Salmo eriox. 

 As to the spawning-time, he had no doubt that the common trout 

 spawned earlier than the other varieties of the salmon. There was 

 a great many common trout of all sizes barren, and it was the com- 

 mon trout caught in January and February that were now coming, 

 in beautiful condition, into the London market. In the beginning 

 of the season they would probably have, out of fifty trout taken, 



