EGG OF ALLOLOBOPHORA FOETIDA. 5 1 



before the first polar body is about to be constricted off, no 

 matter how far the spermatozoon may have penetrated into the 

 ^&S (Fig. 2). And this feature is not confined to this egg; for 

 in studying the literature I have not been able to find any sat- 

 isfactory evidence of the appearance of a sperm attraction 

 sphere earlier than the anaphase of the first maturation spindle. 

 On the contrary, it is distinctly stated that in those cases where 

 the Qgg is fertilized very early (before the first maturation spin- 

 dle is formed), the sperm remains unchanged (sometimes for 





■■..-■ .• 1 ■ 



%:-:vN-i > ?;';^/ •.••■::-•• ■'•".■': 





-^:^Cy.:rmM 



,1 • „ 





''"' '■ ■■■■'.:'.■ .- l/•^^'J^^I^^;f^;^^^:^''•";V■'■■"• •■■ • ■"'■■■i* 



Fig. 4. — Male attraction sphere, showing cytoplasmic network, archoplasm, centrioles, 



and some of the microsomes. 



hours) until the first polar body is constricted off; that there 

 is no interchange of action between the sperm and egg until 

 the first polar body is formed. 



To continue the comparison between the fertilization cone 

 and the sperm attraction sphere: In examining the figures you 

 will find that both structures contain a substance not confined 

 to them but distributed throughout the cytoplasm (Figs. 2, 3, 

 4). (In these figures this substance is represented by the gray 



be so. This possibility is suggested by the fact that the structure found by Fick 

 in the egg of Axolotl, and which is similar to the fertilization cone of Allolobo- 

 phora foetida, appears normally after the first polar body is formed. 



