BROOK OR SPECKLED TROUT. 95 



They continued to move about with less and 

 less vigor for about an half hour, when all motion 

 ceased, owing no doubt to loss of vitality. 



Fig. 2 represents the egg of the trout as it 

 appears when just extruded from the female, 

 magnified about sixteen diameters. The egg is 

 filled with a multitude of cells of various dimen- 

 sions as shown in the cut. 



Fig. 3 gives the appearance of the egg eight 

 days after impregnation. The principal change 

 observable is that the cells are all congregated 

 to one side of the egg. When the egg was agi- 

 tated sufficiently to scatter the cells they were 

 immediately attracted together as before. 



Fig., 4 represents the appearance of the egg 

 at twenty-five days after impregnation. The whole 

 length of the embryo fish is easily traced; the 

 head and eyes are however by far the most dis- 

 tinct. Blood vessels are distinctly seen running 

 in various directions, the aorta in particular be- 

 ing strongly shown. 



Fig., 5 represents the egg at thirty-five days 

 after impregnation. It will be seen that quite 

 a change has taken place in the last ten days : 

 Its vascularity is increased immensely; the ves- 

 sels given off from the aorta being much longer, 

 their ramifications much more extensive, and the 

 outlines of the embryo fish more distinctly mar- 



