242 ON RACES AND HYBRIDS AMONG THE SALMONID.E. [M;ir. 3, 



rising two-3'ear-olcl hybrid fishes, a very important fact must not be 

 overlooked. Last season, 1883-84, it was observed that, although 

 young Salmon-par at just over two years of age could fertilize the 

 ova of Trout, the alevins were dropsical, and only about 100 out of 

 4000 survived. So the experiment was altered this season ; and a 

 young Lochleven Trout rising two years of age was employed to 

 supply the eggs which were milted from an adult of her own race. 



November 13, 1884. — About 500 eggs were obtained from a 

 rising two-year-old Lochleven Trout, their average size being 0'17 

 of an inch in diameter (at 8 years old they are from 0'20 to 0*24 of 

 an inch) ; these were impregnated from a male of average size and 

 of the same race. The eggs were placed in box 124 5 ; and it was 

 observed that besides being small, they had a much thinner shell 

 than had those of older fish. The eggs did very badly, and only 

 about a dozen hatched. This experiment is of very great value, as 

 tending to show that small eggs taken from young mothers have a 

 deficiency of vitality in a similar manner to the milt of the young 

 males. 



On December 9, 1884, about 400 ova were taken from a Howle- 

 toun Grilse and milted from a Lochleven Trout. The diameter of 

 the eggs was 22 inch ; and they were placed in tray 108 b. Only 

 about half the eggs appear to have been impregnated. 



December 13. — 500 eggs were obtained from a dead Sea-Trout 

 which had met its death from direct injury, a wound having ex- 

 tended into the ovary, and possibly water had then obtained entrance. 

 To these eggs the milt of a Salmon par, reared at Howietoun, was 

 added ; and they were deposited in box 84 c. The size of the eggs 

 was 0*18 inch in diameter. Probably none will hatch. 



December 13, 1884. — 6.50 eggs were obtained from a Sea-Trout, 

 and having been impregnated from a Lochleven, they were placed 

 in tray 84 b. The size of each egg was 0'18 inch in diameter, 



November 11, 1884.— About 12,000 eggs of the Lochleven Trout 

 were milted from a Howietoun-reared smolt, and laid down in box 

 No. 1. These eggs have done very well, only about 87 dead ones 

 having been picked out ; they hatched on January 28, and the young 

 look well. In this experiment neither parent was under the third 

 season. 



November 14, 1884. — About 800 eggs of the Lochleven Trout 

 were milted from three Howietoun-reared pars and smolts. These 

 eggs were placed in box 96 a. They hatched on February 5 ; the 

 young are numerous, and appear to be very healthy. The remark 

 on the age of the parents in the last experiment also may be applied 

 to this. 



On November 12, 1884, 1350 eggs of a Lochleven Trout were 

 milted from a hybrid Char and Trout ', this hybrid being 8| inches 

 in length. The eggs were placed in box 92 a ; only about 12 eyed, 

 and out of these 3 embryos came to their full size, but had not suf- 

 ficient vitality to burst their shell, dying unhatched. As a rule, 

 the eggs appeared not to have been impregnated. On measuring 

 ' Proc. Zool. Soc. 1884, p. 586. 



