Vol. XIII. September, igoy. No. 4. 



BIOLOGICAL BULLETIN 



STUDIES ON THE RELATION BETWEEN AMITOSIS 

 AND MITOSIS. 



IV. Nuclear Division in the Somatic Structures of the 



Proglottids of Moniezia. 



V. General Discussion and Conclusions Concerning Ami- 



tosis and Mitosis in Moniezia. 



C. M. CHILD. 



IV. Nuclear Division in the Somatic Structures of the 

 Proglottid of Moniezia. 



1 . The Genital Ducts. 



The various genital ducts of the cestode proglottid appear to 

 arise by the division and differentiation of the parenchymal cells, 

 if the syncytium which composes the parenchyma can properly 

 be said to be composed of cells. 



Moreover, this division and differentiation apparently occurs 

 in situ, at least to a large extent, and not by outgrowth of the 

 cells from a particular region. As was noted in the first paper 

 of this series the development of the reproductive organs begins, 

 or at least first becomes visible, in a region near the longitudinal 

 nephridial canals and the lateral nerve cords, i. e., midway be- 

 tween the region where the ovaries will appear and the lateral 

 border of the proglottid (Child, 'oya, Figs, la, id), the first por- 

 tion to appear being parts of the ducts. The earliest indication 

 of development is an increase in the number of the parenchymal 

 nuclei in this region (Child, 'o"ja, Figs. 2 and 3). The area of 

 proliferation gradually extends in both directions and the "cells" 



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