FERTILIZATION-REACTION IN ECHINARACHNIUS PARMA. 285 



June 14, 3:00 P.M. Eggs examined and counts made for 

 cytolyzing eggs with the following results : 



In this observation we find half the eggs in sea-water cytolyzed 

 seven hours after removal from the female. Eggs treated with 

 butyric acid for ten to twenty seconds fare better in sea-water ; 

 and eggs exposed for the optimum time while cytolyzing in high 

 per cent, at this time still do not show complete cytolysis as do 

 the over-exposed groups. 



Experiment 6 B. June 15, 3:00 P.M. Eggs from one female 

 shaken off ovaries into 10 c.c. of butyric acid sea-water; portions 

 transferred to dishes each with 250 c.c. of sea-water after 15-120 

 seconds as shown below. Control in sea-water. Membranes best 

 after the 35 and 40 seconds exposures, 93 and 90 per cent, re- 

 spectively. A few perfect membranes after 60 seconds exposure, 

 others contracted membranes, 90 and 120 seconds exposures 

 give loo per cent, contracted membranes. 



June 1 6, 8:00 A.M. Dishes examined with the following 

 counts shown : 



No. 



Seventeen hours after treatment with butyric a hundred per 

 cent, cytolysis is shown in the over-exposed eggs. The under- 

 exposed eggs cytolyze at a lesser rate than the control in sea- 

 water. 



Experiment / B. June 16, 7:00 P.M. Dry washed eggs from 

 one female exposed to butyric acid up to 120 seconds (Nos. 

 2-11). Control (No. i in sea-water). Very few membranes 

 after 35 and 40 seconds exposures. 60, 90, and 120 seconds ex- 

 posures give 100 per cent, contracted membranes. 



