GERM CELLS OF COELENTERATES 87 



I found egg cells thus arising, so that such is not the usual method 

 of origin. In the same individual just referred to, most of the 

 egg cells were taking their start in the entoderm, figure 3, for 

 example, being a drawing of a section of the same individual in 

 which numerous eggs were forming in the entoderm. From an 

 examination of many individuals it is clear that the common 

 method of origin of the egg cells in Clava leptostyla is that stated 

 by Goette for C. multicornis, viz., by a division of the entoderm 

 cells in the base of the pedicel of the gonophore, or of the adja- 

 cent polyp wall. Clava, therefore, agrees with Campanularia 

 in the method of origin of the egg. But in Clava such cells may 

 occasionally form in the ectoderm and pass through the sup- 

 porting layer into the entoderm, just as Weismann believed 

 might be the case. 



In forms like Clava and Campanularia, where each primordial 

 germ cell develops directly into a single mature egg, I have 

 found that the only sure sign for distinguishing such primordial 

 cells is the appearance of the nucleus. This is always large, 

 and at an early stage the chromatin is arranged in loops dis- 

 posed in polar fashion toward one side. The cytoplasm is more 

 compact and finely granular and takes a deeper stain with 

 hematoxylin and basic stains than do other cells except gland 

 cells. Only when such differences can be made out is one able 

 to differentiate between the germ cells and the adjoining cells. 

 This distinction is evident as soon as the division of the ento- 

 derm cell has taken place and the nucleus has been reformed. 

 The more usual method of distinguishing germ cells from others 

 is the close packed, deeply staining, granular cytoplasm, but 

 this by itself can not be depended upon and has undoubtedly at 

 times led to error by mistaking gland cells or developing nemato- 

 cysts for germ cells. 



Concerning the claim of Harm that in C. squamata germ cells 

 could be distinguished in the larval stage (planula) nothing posi- 

 tive can be said since it has not been my fortune to see this spe- 

 cies. The same can be said of Gonothyraea loveni in which a 

 similar claim of the differentiation of germ cells in the larva is 

 made by Wulfert ('02). It is, of course, possible that such is the 



