no MARVELS OF FISH LIFE 



The eggs of the anchovy usually hatch in two to three 

 days, those of the sprat in three to four days ; and it 

 is exceptional for any of the eggs of our food fishes to 

 take more than a fortnight. 



The life of the young fish commences as soon as 

 fertilisation of the egg has occurred. After hatching, 

 this life is divided into four stages : larval, post-larval, 

 adolescence and maturity. 



The larval stage extends from the hatching of the 

 fish to the time when the yolk sac is absorbed. When 

 the yolk sac has disappeared the young fish is totally 

 unlike the adult in appearance, and until such time as 

 the appearance of the adult has been acquired the young 

 fish is described as being in the post-larval stage. 



Adolescence covers the period from the post-larval 

 stage to the time when the fish develops spawn, after 

 which it becomes a mature fish. 



Bearing in mind the size of the eggs of the fish under 

 consideration, it follows that the larval forms of our 

 food fishes when first hatched are exceedingly small ; the 

 largest of them, indeed, is only about one-fifth of an 

 inch in length. 



As a typical illustration of a fish just hatched from 

 a marine egg, I show a photograph of the larval plaice. 

 The points of interest in its structure are : the simple 

 median fin running from the head right round the tail 

 to the yolk sac beneath, and the pectoral fin seen as a 

 delicate circular flap. 



In the head we notice the shape of the brain, the 



