No. 3-] EGG OF ALLOLOBOPHORA FCETIDA. 531 



the germinal vesicle that can be clearly differentiated. When 

 a nucleolus is not visible the germinal vesicle looks somewhat 

 opaque, but homogeneous, like fine ground glass. The ger- 

 minal vesicle is always spherical, and its contact with the cyto- 

 plasm complete, while the cytoplasm is in close contact with 

 the cell membrane. This has made us very cautious in draw- 

 ing conclusions from fixed material showing a distorted ger- 

 minal vesicle or cytoplasm torn away from the cell membrane, 

 for a study of the living ^g^ will readily demonstrate that this 

 condition is an artefact. The osmophile granules also show 

 conspicuously in the living tg%, and agree both in size and 

 position with those seen in fixed material. They appear in the 

 substance between the cells and in the small cells (oogonia i") 

 near the proximal end of the ovary. Besides the osmophile 

 granules there are clearer and denser areas, but no evidence 

 of a network, the general effect being homogeneous. In the 

 cytoplasm there is no evidence of hyaline globules such as 

 those described for the later cocoon stages (11 and 12), and 

 if the substance is present in the living ovarian tgg, it is not 

 in the form of globules. It is very difficult to obtain a good 

 fixation of the oocytes, first order (at the distal end of the 

 ovary); nearly all the fixatives which give satisfactory results 

 in the later stages and in the younger ovarian eggs distort 

 the structures in the oocytes, first order, shrinking the ger- 

 minal vesicle and tearing the cytoplasm from the ^gg mem- 

 brane.^ The defense of any structures seen in fixed material, 

 at one stage of development of the ^gg, on the ground that 

 this stage has been subjected to the same technique used for 

 an earlier or later stage, would be quite worthless in the case 

 of Allolobophora, where the only safe criterion is a comparison 

 at each stage of the fixed with the living material. 



Homolognes. — The question as to what extent the archo- 

 plasm of this Q.gg can be homologized with substances in other 

 cells offers an interesting problem. The homology of the 

 yolk-nucleus to substances in other cells has been suggested 

 by various authors, — Nussbaum (28), ('82) ; Balbiani (2), ('93); 



1 Carnoy and Lebrun (5) have experienced a like difficulty for the oocytes, 

 first order (first spindle stage), of Ascaris. "Nous ne connaissons pas encore un 



