1918 



Hall; on Sea-urchin Eggs 



115 



Table 2. Effects of H2SOS on unfertilized eggs 



To test the sensitivity of unfertilized eggs and sperms, the eggs 

 were placed in acid, then taken out and some fertilized in acid and 

 others in sea-water, at definite intervals (table 2). The sperms were 

 motile in the acid but seemed to be inhibited so that cleavage was delayed. 

 However, fertilization took place in all cases, i e., with or without acid, 

 cleavage going to the gastrula stage in a pH of 7.6 — 8.0 (N/15000 — 



