Fish-Hatching in a Current of Water. 93 



its contact with the atmosphere, and is essen- 

 tial to the vivification of the ova. 



It probably happens sometimes that ova 

 which are covered with gravel may, by the 

 subsidence of the stream, be left above the 

 level of the water ; and if the gravel in which 

 they are embedded continues sufficiently moist, 

 these eggs may hatch out safely, and the 

 alevins may reach the water immediately after 

 being hatched; but this must be a very ex- 

 ceptional case, and I cannot imagine such a 

 delicate creature as a newly hatched salmon, 

 if buried even to the depth of an inch or two, 

 unless it be in very coarse gravel, being able 

 to find its way out. 



The parent fishes, if of the migratory 

 species, ascend from the sea into the same 

 rivers in which they were reared, with almost 

 unerring instinct ; it being a very rare thing 

 to find a salmon, bred in one river, ascend- 

 ing another river to spawn. Having found 

 a suitable spawning place, which is generally 

 sought for at or near her own place of birth, 

 the female fish excavates a hollow by the 

 motion of her tail, acting as a fan upon the 

 gravel, which is termed the redd. The male, 



