IIo 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 
