DEVELOPMENT AND GROWTH OF SALMON-FRY. 55X 



ment of the pond, assumed the corresponding silvery aspect of the salmon-fry. 

 The river during this month being remarliably low, I was thus enabled to ascer- 

 tain more accm'ately the time during which they continued to migmte, which I 

 found to be nearly throughout the whole of the month, but more especially in the 

 course of the second week, in which the shoals were both larger, and more fre- 

 quent in their successive arrivals. Their external aspect Avas the same as that of 

 the former shoals, and the average length, as usual, from six to seven inches. 



Having thus traced the progi-ess of the parr from an inch in length, through 

 its several stages up to the period of migration, I shall now detail my various ex- 

 periments on the ova of the salmon, undertaken with a view to prove the identity 

 of these two fish. On the 10th of January 1836, I observed a female salmon of 

 considerable size (about 16 lb.), and two males, of at least 25 lb., engaged in de- 

 positing their spawn. The spot which they had selected for that pm'pose was a 

 little apart from some other salmon which were engaged in the same process, and 

 rather nearer the side, although still in pretty deep water. The two males kept 

 up an incessant conflict during the whole of the day, for possession of the female, 

 and, in the course of their struggles, frequently drove each other almost ashore, 

 and were repeatedly on the surface displaying their dorsal fins, and lashing the 

 water with their tails. Being satisfied that these were real salmon, there being 

 at least ten brace of that fish engaged in the same process on the stream at the 

 time, I took the opportunity of securing as much of the ova as I could possibly 

 obtain. This I did three days after it was deposited, the males and female stiU 

 occasionally frequenting the bed. The method by which I obtained the eggs was 

 by using a thin canvass bag, stitched on a slight frame formed of smaU rod 

 iron, in fashion of a large square landing-net, one person holding this bag a few 

 inches farther down the stream than where the ova were deposited, and another 

 with a spade digging up the gravel, the current carrying the eggs into the bag, 

 while the greater portion of the gravel was left behind. Having thus obtained a 

 sufficient quantity of the ova for my purpose, I placed them in gravel under a 

 stream of water where I could have a convenient opportunity of watching their 

 progress. The stream was pure spring water. On the 26th February, that is, 

 forty-eight days after being deposited, I found on close inspection that they had 

 some appeai-ance of animation, from a very minute streak of blood which appeared 

 to traverse for a short distance the interior of the egg, originating near two small 

 dark spots not larger at that time than the point of a pin. These two dark spots, 

 however, ultimately turned out to be the eyes of the embryo fish, which was dis- 

 tinctly seen resting against the interior smface of the egg a few days previous to 

 its exclusion. On the 8th of April, which makes ninety days imbedded in the 

 gravel, I found on examination that they were excluded from the egg, which was 

 not the case a day or two previous. The temperature of the water at the time 

 was 43°, the temperature of the water in the river 45°, and the temperature of the 



VOL. XIV. PART II. 5 D 



