16 



and lost in the gonads previous to dehiscence. Before fer- 

 tilization the eggs float in a cloud throiigh the v/ater, 

 each one surrounded by a very soft thick gelatinous envel- 

 ope. If the eggs are not fertilized, the surro'anding mass 

 of semi-fluid jelly slowly shrinks up, and the increased 

 specific gravity causes the eggs to sink to the bottom. 

 Blister-like vacuoles appear in the substance of the egg, 

 puffing out the envelope, and in the course of several days 

 the protoplasm becomes disintegrated and the egg goes to 

 pieces. 



When fertilization takes place, the shrinking of the 

 egg- envelope iti more immediate, and greater in degree, so 

 that the egg sinks at once and sticks to the bottom by 

 means of the viscid substance of the surrounding envelope, 



METHODS - 



The adhesive property above referred to is of great 

 assistance in making preparations of the segmenting eggs, 

 as they may be allowed to settle on glass slides, which are 

 afterwards run up through all the reagents without danger 

 of washing off. For sectioning, the best method of secur- 

 ing the eggs was found to be by stirring about in the water 

 with a camels-hair brush, and preventing them from gluing 



