Artificial Parthenogenesis in Starfish Eggs 



TABLE IV— Continued 



399 



In the above three series a large number of eggs reached the 

 larval stage, Series I being especially favorable. In two other 

 similarly conducted series the eggs proved inferior, only about lo 

 per cent undergoing maturation. In the first of these series 

 August 10, 1907, larvae were obtained only from eggs warmed at 

 periods corresponding to Nos. 5 and 8 of the above series; the 

 second, August 13, proved somewhat more favorable, blastulae 

 resulting from eggs exposed at periods corresponding to Nos. 

 4, 5, 6, 7, 8 and 9 above with the optimum at Nos. 6 and 7. The 

 suppression of maturation in eggs warmed within 5 to 10 minutes 

 after removal also resulted in both series. Three other similar 

 series — July 29, July 30 and August 3 — also showed the same 

 suppression of maturation in eggs heated directly after removal. 

 The eggs in these series were inferior and no larvae were obtained; 



