276 JACQUES LOEB AND F. W. BANCROFT 



On the eighth day, the larvae arising from the fertiUzed eggs 

 were swimming. Among the larvae arising from the unfertilized 

 punctured eggs only 3 were normal, and their development was 

 slightly retarded, perhaps one day. In addition, 6 partheno- 

 genetic larvae were abnormal but still alive. 



On the thirteenth day, 2 of the parthenogenetic larvae were 

 feeding and these were the only ones which survived definitely. 

 The other parthenogenetic larvae all died during the next few 

 days. Of the 2 surviving larvae, one went through metamor- 

 phosis after five months. When it died, the tail was almost com- 

 pletely absorbed (fig. 1). Its death was probably accidental. 

 The other lived a month longer and formed small hind legs, but 

 died in the tadpole stage (fig. 2). 



The sex glands of the frog were taken out, hardened in Tellyes- 

 nicki's fluid and sectioned; those of the tadpole were removed 

 after it had been preserved in formalin for several months. 



It was found that both parthenogenetic tadpole and frog were 

 females (fig. 3). 



This result should be expected if the frog belonged to that 

 group of animals in which the female is heterozygous for sex. 



Part of these experiments were made in the laboratory of the 

 University of North Carolina," and we take pleasure in thanking 

 Prof. H. V. Wilson for the many courtesies shown to us. 



