STUDIES ON THE RELATION BETWEEN AMITOSIS 



AND MITOSIS. 



I. DEVELOPMENT OF THE OVARIES AND OOGENESIS IN 



MONIEZIA. 



C. M. CHILD. 



I. INTRODUCTION. 



Some years ago, during an examination of certain abnormali- 

 ties l in Moniesia, the apparent infrequency or total absence of any 

 evidence of mitosis even in regions where rapid growth was taking 

 place attracted my attention. Further investigation showed what 

 various authors had already noted, viz., that anything even re- 

 motely resembling mitotic divisions was either entirely absent or 

 extremely rare in most of the growing regions. Nevertheless, a 

 rapid multiplication of nuclei was occurring in these regions as 

 could readily be determined merely by the examination of sec- 

 tions of successive proglottids or more exactly by counting 

 nuclei in well-defined corresponding regions of different proglot- 

 tids. It was soon possible to establish, beyond a doubt, the fact 

 that the characteristic form of nuclear division was amitotic, not 

 mitotic, no single case of mitosis ever having been seen in most 

 parts of the body. 



Naturally the next step was to determine whether the devel- 

 opment of the germ cells followed the same course. The present 

 and following papers are devoted to a consideration of the results 

 of these investigations. 



The species used are Moniezia expansa (Blanchard) and Mon- 

 tezia pianissimo. (Stiles and H assail) both tapeworms of the 

 sheep, which may be obtained in great abundance from the 

 Chicago Stockyards at certain seasons. The work was begun 

 without any preconceived opinions, but as it progressed it be- 

 came evident that the facts could not be made to agree with the 

 views commonly accepted among cytologists. For this reason 



'Child, "Abnormalities in the Cestode Moniezia Expansa, I. and II.," BlOL. 

 BULL., Vol. I., Nos. 5 and 6, 1900; III., ibid., Vol. III., Nos. 3 and 4, 1902. 



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