PHOTOGRAPHS OF THE EGG OF ALLOLO- 

 BOPHORA FCETIDA. H. 



FURTHER NOTES ON YOLK-NUCLEUS AND POLAR RINGS. 

 KATHARINE FOOT and ELLA CHURCH STROBELL. 



In 1898 Van Bambeke (30) published an important con- 

 tribution to the problem of the yolk-nucleus. He adduces 

 most convincing evidence that the yolk-nucleus substance, 

 after reaching its stage of disintegration (desagregation, Dwr- 

 cellement), becomes directly metamorphosed into deutoplasmic 

 (fat) granules ; these in turn being sacrificed to the formation 

 of the sphtres vitellines. " On pent dire que I'apparition des 

 granules adipeux est le signal de celle des spheres vitellines. 

 Grace a I'appoint fourni par ces granules, le cytoplasme ovu- 

 laire mieux nourri, devenu plus actif, secrete ou elabore les 

 materiaux qui constituent les spheres vitellines," p. 550. 



The author's arguments and figures presented such a strong 

 case, with conclusions so opposed to our earlier interpretation 

 of the phenomenon in the egg of Allolobophora — where we 

 claim that the yolk-nucleus substance contributes to the for- 

 mation of the polar rings — that we were led to reinvestigate 

 the problem, collecting fresh material for this purpose in the 

 summer of 1899. A comparison of Van Bambeke's PI. XXHI 

 with the photos of the young oocytes of our PI. XLI will show 

 that the denser areas in the cytoplasm of our sections are mor- 

 phologically identical with the substance Van Bambeke calls 

 corps vitellin (yolk-nucleus). Cf. also Photo 90, PI. XLV (a 

 reproduction of Van Bambeke's Fig. 9, PI. XXV), with our 

 photos of scattered and peripheral archoplasm, PI. XLI, Photos 

 11-23. Further, his fat (deutoplasmic) granules are undoubt- 

 edly the same substance as our osmophile granules.^ These 



1 The term "deutoplasmic " was used to designate these granules in an earlier 

 paper {9). 



