GERM CELLS OF COELENTERATES 11 



in this region, either in ectoderm or entoderm, which has such 

 an appearance; also it has certain obvious differences from all 

 the adjacent ectoderm cells, and just as obvious resemblances 

 to a young oocyte. This cell is the only one found which pre- 

 sented such an appearance; neither in ectoderm nor entoderm of 

 any of the material could a similar cell be discovered. One cell 

 is not sufficient to warrant any conclusions with respect to the 

 interpretation of this appearance, but in view of its similarity 

 to such stages in Campanularia, Clava, Aglantha, and other 

 coelenterates, it may possibly be of the same nature. A con- 

 siderable amount of material was used, secured at slightly dif- 

 ferent times, and many sections made; just why the early stages 

 so clearly demonstrated in other forms were so rare (or absent) 

 in Eudendrium is not known. The material used showed in 

 every case the beginning of gonophore formation, and it is pos- 

 sible this is too late to show the origin of egg cells, but from 

 every colony younger portions devoid of gonophores were exam- 

 ined and one would expect the germ cells to be in an immature 

 condition if they were present. 



The place of origin of egg cells in this form cannot be posi- 

 tively determined from the material at hand, though I incline 

 to the opinion that it is the ectoderm and that the .small cell 

 ov of figure 9 marks the earliest differentiation of such a cell. 

 In this respect my observations confirm the belief of some 

 workers and are opposed to those of others; but the place of 

 origin is not, in my opinion, a matter of especial significance, 

 and I agree with G. W. Hargitt ('04) and Goette ('07) that there 

 may be variation in the place of formation of the germ cells in 

 hydroids, perhaps even in the same species. The place of origin 

 not having been demonstrated, the method of origin is likewise 

 uncertain. In Gampanularia and Clava the derivation of 

 germ cells from the tissue cells was clear; the position of the 

 smaller egg cells in Eudendrium resembles that of these other 

 forms. Again one may have the suspicion that Eudendrium 

 agrees in a general way with the method of germ-cell formation 

 of those forms, but no more may be said on the evidence obtained 

 from this study. 



