A STATISTICAL STUDY OF MITOSIS AND AMITOSIS. 247 



Quite recently, in fact after the present paper had gone to 

 press, I received a reprint of the memoir " On Tnrritopsis 

 (McCrady)," Proc. Bost. Soc. Nat. Hist., Vol. 33, No. 8, by 

 Professors Brooks and Rittenhouse. These authors record the 

 occurrence of direct nuclear divisions during the development of 

 Turritopsis \ and incline toward the conception of Flemming and 

 Ziegler, that amitosis is connected with cellular specialization or 

 degeneration, as the process is most abundant in Tnrritopsis 

 shortly before cell boundaries disappear and the embryo becomes 

 transformed into a syncitium. As the adult is derived from this 

 syncitial embryo it is not unreasonable to consider the amitoses 

 in question as developmentally significant parts of a normal 

 cycle, as stages in the establishment of adult definitive tissues, a 

 view supported by the evidence recorded in the preceding pages. 



LITERATURE. 



Calkins, Gary N. 



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