34 ROBERT W. HEGNER 



13. A uninucleate-half of a specimen was formed by a normal 

 binucleate, which later gave rise to normal binucleate offspring. 

 This uninucleate-half produced uninucleate offspring which 

 passed through empty shell formation and nuclear doubling 

 just as did those derived from uninucleate-halves obtained by 

 cutting. When a uninucleate from this line was bisected, the 

 nucleated piece behaved as did those described in paragraphs 

 11 and 12. It is probable that pieces resulting from the action 

 of mechanical factors that occur in nature react in a manner 

 similar to those obtained in the laboratory by means of opera- 

 tions. The race is thus not permanently affected by acci- 

 dental mutilations of its members. 



14. The removal of one nucleus from binucleate specimens 

 results in uninucleate specimens containing an amount of cyto- 

 plasm larger than that usually associated with one nucleus. In 

 most cases such specimens form empty shells and become binu- 

 cleate at once. When uninucleate offspring are produced, 

 these are larger than those formed by uninucleate parents with 

 only half of the cytoplasm of the original parent, and they 

 undergo empty shell formation and nuclear doubling more 

 quickly than the latter. This is probably due to the inequality 

 between the single nucleus and the large cytoplasmic mass, 

 and suggests that the process of nuclear doubhng is initiated 

 when the cytoplasmic mass becomes greater than the quantity 

 normally associated with one nucleus. 



15. Operations similar to those siunmarized in the above 

 paragraphs were performed on specimens belonging to two other 

 families with the same results. In one case (line 155) a speci- 

 men was cut into four pieces, and the descendants of the two 

 nucleated quarters eventually regained the characteristics of 

 the original line. 



