HATCHING TROUT 146 



Egg Development. — ^After a lapse of froin ten 

 to twelve hours, a perfectly fertilised brook 

 trout Qgg, when held to the light, shows what 

 appears to be several globules not unlike air 

 bubbles crowded about the micropyle. They 

 are so small that only the sharp eyes of an ex- 

 pert can detect them, a microscope being neces- 

 sary to aid the sight of the unskilled. In addi- 

 tion, the Qgg has a delicately coloured, clear, 

 translucent appearance. After a lapse of three 

 or four days these globules become elongated, 

 and otherwise change to somewhat the form of 

 the spreading roots of a tree. About a week 

 or ten days later, the globules have disappeared 

 and in their place there is a very indistinct 

 outline of a little fish. 



Growth of the Embryo. — ^Day by day the out- 

 lines grow more definite, yet only to be detected 

 by a sharp and practised eye, until, when the 

 egg is from eighteen days to three weeks old, 

 two intensely black spots set close together are 

 plainly visible. These are fish's eyes, — ^the first 

 unmistakable view of the embryo observable. 



Next is sharply outlined a jetty V, the two 

 points of which touch the eyes. These converg- 



