OF GREAT BRITAIN. 3 



according to the temperature of the water. Eggs 

 remaining unhatched beyond the latter period will 

 seldom hatch at all, possibly from having been 

 destroyed by the low temperature. 



3. The eggs deposited by the female will not 

 hatch under any circumstances unless vivified, 

 after exclusion, by the milt of the male ; and — at 

 least up to the period of migration — there is no 

 difference whatever in fry bred between Salmon 

 only, between Grilse onl)', between Salmon and 

 Grilse, between Salmon and Parr, or between 

 Grilse and Parr. ' The female Parr cannot spawn ; 

 but the male Parr possesses, and constantly exer- 

 cises, the power of vivifying Salmon and Grilse 

 eggs. 



\_Note '. — This is to be understood as referring to the specific 

 characteristics of any of the Sahiion thus bred. It seems 

 very probable that there may be in fry variations of size or 

 development depending on their parentage or generation, 

 as there are also known to be differences in the size of the 

 eggs of different breeding fish dependent upon the size and 

 age of the latter.] 



4. The fry remain one, two, and, in some cases, 

 three years in the rivers as Parr before going down 

 to the sea, — about half taking their departure at 

 one year, nearly all the others at two years, and 

 the remainder (which are exceptional) at three 

 years old. 



5. All young Salmon-fry are marked with bluish 



