DEVKLOPMENT AND GROWTH OF SALMON-FRY. g^jg 



While the males of the three several broods which occupy ponds No. 1, 2, 

 and 3, continued in a breeding state, which lasted throughout the whole of the 

 winter of 1838-39, I impregnated the ova of three adult female salmon fi-om the 

 river with the milt of a male taken from each of the three ponds, the whole of 

 which ova matured. This at once removes any doubt which may have been en- 

 tertained regarding the constitutional strength of individuals reared under such 

 circumstances. 



Specimen No. 12, is one of the males used in the above experiments, and is 

 itself the produce between a male parr and female adult salmon taken from the 

 river on the 4th January 1837, and reared in pond No. 2, as already mentioned. 

 The result of the experiment practised Avith this specimen and the female salmon 

 from the river, being of the utmost importance in establishing the identity of the 

 species (on a principle recognised by physiologists as a law of nature), every ne- 

 cessary precaution to avoid error or confusion was observed. It was taken from 

 pond No. 2 on the 5th January 1839, being then twenty months old, with the 

 milt flowing from its body. A female adult salmon Aveighing twelve lb. (see 

 parent specimen, B.) was taken at the same time from the river, in the act of 

 spawning in the absence of the male. A quantity of her ova was impregnated 

 in the same manner in every respect as practised in the preceding experiments, 

 and, for the better security of the lot, the whole was placed in a wooden trough, 

 over which a sheet of fine copper-wire gauze was fixed. The trough was then 

 placed in a stream of water previously prepared for its reception, and the results 

 were precisely of a corresponding nature to those already detailed, the embryo 

 fish becoming visible after fifty-five days, and being excluded from the egg at 

 the end of 109 days after impregnation, under a temperature of 40°. 



It has been maintained by individuals whose opinions are opposed to mine 

 on this question, that the parr is a distinct species, and that, by a forced connec- 

 tion between it and the female salmon, I was producing a hybrid. This idea at 

 once brings the importance of the last experiment more immediately into view, 

 from the circumstance of the male parent of specimen No. 12 being actually a 

 parr, while No. 12 itself, the alleged hybrid, in its turn became the parent of a 

 numerous brood. (See specimens, B.) 



Were these two species, then, reaUy distinct, it would follow that the pro- 

 duce would be hybrids, and " nature herself has provided against the confusion 

 of different species by a conservative law, according to which all hybrids are 



female with which the four parrs above alluded to were spawned. They were placed in the same stream 

 but in a separate vessel from the four lots impregnated. The other lot was taken from the female with 

 which the male from pond No. 3. was spawned. The unimpregnated lot was placed in the same stream 

 with the former. The impregnated lot was placed in the stream of pond No. 3. To avoid contact the 

 unimpregnated lots were in each case taken first, and removed to a distance. 



VOL. XIV. PART II. 5 G 



