3i6 



ELEMENTS OF BIOLOGY 



OOGENESfS 



DIVISION PERIOD 



GROWTH PERIOD 



SYNAPSIS 



Isr MATURATION DIVISION 



CHROMOSOMES REDUCED 

 TO HAPLOID NUMBER. 



2no maturation DIVISION 



PRIMORDIAL GERM CELL 



(.DIPLOID CHROMOSOME 

 NUMBERS 



OOGONIA 



OOCYTE X 



OOCYTE U 



l$T POLAR BODY 



OOTID 



2nd polar BODY 



OVUM 



Fig. 202. — Diagram of the maturation of ova. The mature ovum shown appears 

 again in Fig. 203. For convenience the Y chromosome is omitted. 



