272 - Multicellular Animals, Especially Man 



CYTOPLASM 



NUCLEUS VITELLINE 

 , MEMBRANE 



NUCLEUS 



\ 



"MICROPYLE 

 -CYTOPLASM 



-NUCLEUS 

 -YOLK 



— VITELLINE 

 MEMBRANE 



^CHORION 



Fig. 15-1. Types of egg cells: A, homolecithal egg; B, telolecithal egg; C, centrolecithal 

 egg (of an insect). 



SPERM TAIL 



FERTILIZATION CONE 



FERTILIZATION MEMBRANE 



POLAR BODIES 



Fig. 15-2. Fertilization and early development of a homolecithal egg (starfish). 



