NUCLEAR VOLUME AND LIFE-CYCLE OF HYDATINA 



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9 10 11 12 13 14 15 16 17 18 19 

 Generations 



Fig. 1 Curves representing the relative nuclear volume in three tissues of the 

 rotifer Hydatina senta, in relation to periods of male-production. First curve, 

 the percentage of male-producers in each of nineteen successive generations, 

 showing two distinct periods of male-production. Second curve, the relative 

 volume of nuclei in the yolk gland during the same nineteen generations. Third 

 curve, relative nuclear volume in the stomach-intestine during the same nineteen 

 generations. Fourth curve, relative nuclear volume in the oocytes. 



