THE BIOLOGY OF THE CELL SURFACE 



ing ink which extends into the jelly hull where the sper- 

 matozoon is located. 



The entrance-cone below the spermatozoon now gradually 

 recedes and pulls the membrane along with it so that the 







PiiiP 



V 5 • • • 



'•• 





to 



Fig. 24. — The fertilization-cone and sperm-entr\' in the egg of Rhynchelmis 



(after Vejdovsky and Mrazek). 



spermatozoon lies in a depression. During these minutes 

 the egg undergoes the irregular changes of form and darken- 

 ing already described in the chapter on the general prop- 

 erties of the ectoplasm. When it regains regular form and 

 clears, twenty-five minutes after insemination, the cone is 



160 



