296 ADDITIONAL NOTES. 



stated, as I have been informed by Mr. Yarrell, that in rivers in 

 which the smolts (supposed to be of two years) descend to the 

 sea in April and May, there are to be met with in July and 

 August two apparently distinct broods, judging from difference 

 in size, a larger and a smaller, the larger taking the artificial 

 fly, and, in consequence, well known to anglers, varying from 

 four to seven inches in length ; the smaller, little known, from 

 not taking the artificial fly, not exceeding in length from two to 

 two and a half inches. It may be said that these smaller fish are 

 from ova laid early in the spring, the larger from ova deposited 

 late in the autumn. The difficulty of deciding which inference 

 is the true one, in great part arises from not knowing the rate of 

 growth of the young fish in different rivers and under different 

 circumstances, that seeming in great measure to depend on its 

 supply of food. Judging from the analogy of the trout, and the 

 rapid growth of the young salmon after entering the sea, it is 

 easy to imagine that a parr, well fed, may attain its full average 

 river-size in a few months ; or, on the contrary, if ill fed, may 

 be checked in its growth, and be stationary in its size for many 

 months. The mountain-brook trout is an instance of the slow 

 growth and diminutive size, inhabiting waters where there is 

 little and precarious food ; the river or lake trout, feeding plen- 

 tifully and growing rapidly, is an instance of the other kind. I 

 have heard it asserted by an experienced keeper, that he could, 

 by a peculiar mode of feeding, augment a trout in weight two 

 pounds in as many months, viz. by suspending a dead rabbit 

 from a branch of a tree over the haunts of the trout. The 

 rabbit, he said, became fly-blown, the maggots resulting fell 

 into the river, and the trout feeding on them, grew and fattened 

 thus rapidly. 



But whether the young fish be one or two years, or an inter- 

 mediate period or a longer period, in assuming the smolt form, 

 it now seems tolerably well proved that the testes of the young 

 salmon are fully developed, so as to be capable of exercising a 

 fertilising influence, before descending to the sea ; but that the 

 ovaries are later in their growth, and the ova are not mature till 

 the fish has returned from the sea as a grilse. And does not this 

 warrant the conclusion, that the ova of the latter are fertilised 

 by the sperm of the former 1 Such observations as I have made 

 in examining the testes and ovaries of the salmon-fry at different 



