28O HELEN DEAN KING. 



nucleus had fused with the egg-nucleus, however, and the seg- 

 mentation-spindle that was formed usually appeared normal, 

 although in many cases it occupied a very eccentric position close 

 to the periphery of the egg. All of the accessory spermatozoa 

 at this time were in the form of a small, rounded nuclei that were 

 scattered throughout the cytoplasm. 



The ^ per cent, solution of aspartic acid had a different action 

 on different eggs, depending, doubtless, upon the condition of 

 the eggs when they were placed in the solution. Five hours after 

 the experiment was begun about one fourth of the eggs were still 

 unsegmented; some of the eggs were just beginning to segment; 

 while others were in later stages of segmentation, and the cleavage 

 planes were coming in very irregularly in many cases. A very 

 few eggs had reached the blastula stage at this time, but they 

 \vere not as well developed as the eggs in the control lot. After 

 twenty-two hours the number of eggs that had reached the 

 blastula stage was found to be consideraly increased. Develop- 

 ment had been checked by this time, however, and the greater 

 number of larvae appeared as more or less irregular masses of 

 cells that w r ere beginning to disintegrate. 



Preparations of this material showed many cases of polyspermy. 

 Some of the unsegmented eggs contained a large multipolar 

 segmentation-spindle formed, evidently, by the fusion of several 

 sperm-nuclei with the egg-nucleus: other eggs contained a seg- 

 mentation-spindle of the normal size with the chromosomes very 

 unequally distributed to the spindle poles. The condition of 

 these eggs greatly resembled that which O. and R. Hertwig ('87) 

 found could be induced in fertilized echinoderm eggs by subjecting 

 them to the action of various chemical substances which pre- 

 vented their normal development. 



Asparagine (C 4 HioNiO.i). This amide of aspartic acid proved 

 to be far less injurious to the eggs of Arbacia than did the latter 

 substance, when used in solutions of the same strength (l, J-, -^ 

 and 3\y per cent.). The great majority of the eggs in all of the 

 cultures began to segment at the normal time and in a normal 

 manner. After two hours the eggs in the I per cent, solution 

 showed evidence of retarded development, but the eggs in all 

 of the other solutions developed at a normal rate for some hours. 



