168 Mr Shaw's Experiments on the Fry of the Salmon. 



by the aid of the stream. In capturing these fish, I consider- 

 ed myself fortunate in securing them by one cast of the net, 

 for, in conducting the experiment of artificial impregnation, it 

 appears to me to be very desirable that the male should be 

 taken, with the female of his own selection, at the very moment 

 when they are mutually engaged in propagating their species. 

 To take a female from one part of the stream and a male from 

 another, might not give the same chance of a successful issue 

 to the experiment. Having drawn the fish ashore, I placed 

 the female, while still alive, in the trench, and pressed from her 

 body a quantity of the ova. I then placed the male in the same 

 situation, pressing from his body a quantity of the milt, which, 

 passing down the stream, thoroughly impregnated the ova. I 

 then transferred the spawn to the basin, and deposited it in a 

 stream connected with a pond previously formed for its recep- 

 tion, which, however, I have not considered it necessary to re- 

 present in the accompanying plan. The temperature of this 

 stream was 39*^, of the river from which the salmon were taken 

 S3°, and of the atmosphere 36°. The skins of the parent sal- 

 mon are now in my possession. 



On examining the ova on the 23d of February (fifty days 

 after impregnation), I found the embryo fish distinctly visible 

 to the naked eye, and even exhibiting some svmptoms of vita- 

 lity by moving feebly in the egg. The temperature of the stream 

 was at this time 36°, and of the atmosphere 38°. On the 28th of 

 April (114 days after impregnation) I found the young sal- 

 mon excluded from the egg, which was not the case when I 

 visited them on the previous day. The temperature of the 

 stream was then 44°. On its first exclusion, the little fish has 

 a very peculiar aspect. The head is large in proportion to the 

 body, the whole fish measuring f ths of an inch in length, and 

 of a pale blue or peach-blossom colour. The bag, which at 

 this early age is appended to the upper part of the belly, pre- 

 sents a very singular appearance. It is of a conical shape, the 

 base being attached to the fish. It measures about fths of an 

 inch in length, is of a beautiful transparent red colour, very 

 much resembling a light red currant, and is easily distinguish- 

 ed at the bottom of the water, even when the fish itself can with 

 difficulty be observed. A slightly indented fin or fringe re- 



