EGG OF ALLOLOBOPHORA FOETID A. 



49 



from the ^%,^ centrosome ? Is the male centrosome the middle- 

 piece, or any part of the middle-piece, of the spennatozobn ? 

 The phenomena of fertilization in the egg of Allolobophora 

 foetida warrant a negative answer to this question. I am aware 



Fig. 3. — Optical section of entire egg, showing telophase of first maturation spindle, head of sper- 

 matozoon, with male attraction sphere and archoplasm in the sphere, spindle, and throughout 

 the cytoplasm (microsomes not represented). 



that a denial of such a generally accepted view demands the 

 strongest evidence for its support, and I confess that the only 

 evidence I can at present produce is that of differential stain- 

 ing. One of the facts justifying the assertion of the identity 

 of the male centrosome with the middle-piece of the spermato- 

 zoon is that both structures have been shown to select the same 



