THE SALMON FAMILY. 241 



3. The eggs deposited by the female will not hatch 

 under any circumstances unless Advified, 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 GrDse only, between Sal- 

 mon and Grilse, between Salmon and Parr, or between 

 Grilse and Parr. 



[iVbfe. — The female Parr cannot spawn ; but the male Parr pos- 

 sesses, and constantly exercises, the power of vivifjing Salmon 

 and Grilse eggs.] 



4. The fry remaiQ 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 bars 

 on their sides until shortly before their migration, up to 

 which period they are Parrs ; they then invariably assume 

 a more or less complete coating of silvery scales and be- 

 come Smolts, — the bars, or Parr-marks, however, being 

 still clearly discernible on rubbing off the new scales. 



6. The young of all the species here included in the 

 genus Salmo have at some period of their existence these 

 bluish bars; and consequently such marks are not by 

 themselves proofs that fry bearing them are the young of 

 the true Salmon {Salmo salar). 



7. Unless the young fish put on their Smolt dress in 



