THE BIOLOGY OF THE CELL SURFACE 



and when laid are in the stage of second maturation. 

 They possess a strongly marked ectoplasm which remains 

 wholly colorless after treatment with a dye which stains 

 the yolk-spheres. This ectoplasm is made up of spheres 

 lying among a fine net-work composed of radially projecting 





\-:-V;;;;/^ 'yi'yvv-v:-:' 



^ / 



Fig. 28. — For descriptive legend see page 169. 



Strands of the egg-plasma. (See figure in the chapter, 

 The Ectoplasm, p. 99.) 



On entrance of the spermatozoon, which takes place at 

 the vegetal pole, the ectoplasm breaks down; according to 

 Cerfontaine it begins to go into solution at the site of sperm- 

 entry. The ectoplasmic spheres seem to liquefy and 

 become confluent. Both Sobotta and Hatschek affirm that 



168 



