542 



PRODUCTION OF PARTHENOGENETIC FROGS 



sterilized instruments. The hands of the experimenter were also 

 sterilized. About 50 to 100 eggs were put on each glass slide and the 

 eggs of every second or third slide were not punctured, serving as 

 controls. In no case did a single control egg show any development; 



Fig. 3. Section through the ovary shown in Fig. 2. 



only punctured eggs developed. This excludes the idea that the eggs 

 were fertilized. 



There remain other possibilities to account for the fact that the 

 chromosome number is diploid. As Parmenter states^ 



