462 



A. FRANKLIN SHULL 



TABLE 7 



Frequency of occurrence of aberrant numbers of nuclei in the gastric glands of Hy- 



datina senta in periods of many male-producers and in periods of 



few male-producers 



TABLE 8 



Frequency with xvhich aberrant numbers of nuclei occur in the gastric glands of 



Hydatina senta, in young and middle-aged adults, respectively {no old 



adults were examined) 



TABLE 9 



Proportion of gastric glands having aberrant numbers of nuclei in individuals of 

 Hydatiiia senta reared, respectively, in spring water and in manure solution 



TABLE 10 



Proportion of gastric glands, in male-producing and female-producing individuals 

 of Hydatina senta, having aberrant numbers of nuclei 



