GERM CELLS OF COELENTERATES. 11. CLAVA 

 LEPTOSTYLA 



GEORGE T. HARGITT 



Zoological Laboratory, Syracuse University 



ELEVEN FIGURES (TWO PLATES) 



In part I of this series the oogenesis of one of the campanu- 

 larian hydroids (Campanularia flexuosa) was described in detaiL 

 It was there pointed out that an egg cell arises in the entoderm 

 from one of the ordinary epithelial cells or from a part of such 

 cell as a result of division, and this, it was believed, demonstrated 

 the absence of any differentiation of a distinct germ plasm. A 

 single primordial cell develops directly into a single egg cell 

 without intervening cell divisions, therefore without genera- 

 tions of oogonia and oocytes. 



The chromatin of the nucleus of the growing oocyte was partly 

 in a nucleolus and partly in a delicate and fine meshed reticulum. 

 During growth the nucleolus broke into small fragments which 

 passed out into the cytoplasm to form, or to aid in forming, the 

 yolk. Since the growth of the egg began with this emission of 

 chromatin from the nucleus and ceased when this emission had 

 been completed it was clear that such emission had some causal 

 connection with the metabolic activities of the developing egg. 



It was also noted that in Coelenterates the place of origin of 

 the germ cells is not now of fundamental importance, since 

 Goette ('07) and others have shown how variable it may be 

 even in different individuals of the same species. There is, how- 

 ever, still some difference of opinion with regard to the origin of 

 the germ cells of Clava and the present report may aid in har- 

 monizing in some measure these divergent views. 



In Clava squamata Weismann ('83) described the egg cells as 

 first distinguishable in the entoderm, close to the supporting layer. 

 He suggests a probable ectodermal origin and a migration through 



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