Effect of a Centrifugal Force upon Development and Sex 13 I 



and on March 8, at 10 a.m., four young daughter-females were 

 present in the dish. This female produced twenty-nine eggs 

 which developed into females. Two of these daughter-females 

 matured and produced males and twenty-seven matured and 

 produced females 



Experiment XXXIII. The conditions, size of egg, and the 

 arrangement of egg material in the first cleavage were approxi- 

 mately the same as in Experiment XXXI. A normal young 

 female developed from the egg, matured and produced males. 



Experijnent XXXVII. March 5, at 2:15 p.m., a female con- 

 taining a large egg was centrifuged. At 4:30 p.m., the egg that 

 had been laid was in the first cleavage stage. The small cell 

 included portions of the pink and clear zones, Fig. 4. 



On March 6, at 11 a.m., a normal young female was swim- 

 ming about in the dish. Food was added. This female grew to 

 maturity and produced twenty-five eggs, all of which developed 

 into females. One of these daughter-females matured and pro- 

 duced males and twenty-four matured and produced females. 



Experiment XLIV. The conditions, size of egg, and the ar- 

 rangement of the egg material in the first cleavage were approxi- 

 mately the same as in Experiment XXXVII. A normal young 

 female developed from the egg, matured and produced twenty- 

 five eggs, all of which developed into female-laying females. In 

 later generations males appeared. 



Experiment XXXII. March 5, at 2 115 p.m., a female containing 

 a large egg was centrifuged. At 3:30 p.m., an egg had been laid 

 and was in the first cleavage stage. The small cell included por- 

 tions of the three zones (Fig. 5). 



On March 6, at 9 a.m., a normal young female was present in 

 the dish. Food was added. This female matured and produced 

 only three eggs. One of these eggs developed into a male-laying 

 female and the other two developed into female-laying females. 

 This small production of eggs was due to the scanty amount of 

 food given to the female. 



Experiment L. March 10, I p.m., a female containing a large 

 egg was centrifuged. At 3 p.m., the egg had been laid and was 

 in the first cleavage stage. The small cell contained about two- 



