460 



A. FRANKLIN SHULL 



TABLE 4 



Distribution of aberrant numbers of nuclei in the yolk glands of individuals of Hy- 



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



TABLE 5 



Frequency of occurrence of aberrant numbers of nuclei in the yolk glands of rnale- 

 producing and female-producing Hydatina senta 



these tables to justify the computation of percentages with the 

 expectation of making vahd comparisons. There are, however, 

 no striking differences in the numbers of aberrant glands under 

 different circumstances. Yolk glands with other than eight 

 nuclei occur at times of many male-producers, as well as at times 

 of few; in young, middle-aged, and old females; in specimens 

 reared in spring water, and in those reared in manure solution; 

 in male-producers as well as in female-producers. And they 

 occur with what might well be equal frequency, if the numbers 

 examined were large enough, in each of these cases. 



It seems unlikely, therefore, that any of the conditions above 

 enumerated have anything to do with the alteration of the num- 

 ber of nuclei. It is also worthy of note that the deviations from 

 the usual number eight are not all diminutions, as Martini (see 

 ante) found in the case of the stomach-intestine. It may also be 

 remarked that the only deviation in a young adult female was 

 a, plus deviation (table 3), which cannot therefore be explained 

 by supposing that not all the usual cell divisions had yet occurred. 



