52 HATCHING AND GROWTH OF THE FEY. 



the power of a current they can withstand, that such 

 small creatures are endowed with such wonderful mus- 

 cular power. 



The ova remain in the spawning-beds for from two 

 to four months, according to the temperature, before the 

 young fry are excluded, which is generally some time 

 in April ; but the period of their hatching is either con- 

 siderably expedited or retarded, according to the general 

 mildness or severity of the season. It would appear, 

 from observations recently made, during the artificial 

 breeding of salmon, that the rays of light exert an in- 

 jurious influence, both upon the impregnated ova, and 

 the newly-hatched fry ; causing the former to become 

 of a dull white colour, and to prove abortive ; while, if 

 the latter are exposed to it during the first ten days of 

 their existence, the yolk-bag, which remains suspended 

 to the abdomen, for the purpose of supplying them with 

 nourishment until they are able to seek food for them- 

 selves, speedily shrivels up, and the death of the parrlet 

 is the result. It will thus seem that the fry necessarily 

 remain concealed from light for a short period after they 

 are excluded, among the interstices of the gravel. 



When well fed, the fry are said to grow rapidly ; 

 and according to some experiments instituted for the 

 purpose of ascertaining the rate of their growth, they 

 have been found to attain the length of six inches in six 

 months, and from eleven to fifteen inches in fifteen 

 months ; while at the end of two years some of the fish 

 in the pond where the experiment was made had attained 

 the length of twenty-two inches, and a weight of three 



