OVULATION AND EGG TRANSPORT 



RANA PIPIENS 



109 



ANIMAL WXE 



j , GERMINAL VESICLE 



WITH CHROMOSOMES 



METAPHASE OF 

 SECOND MATURATION 



2 POLAR SOOIES 



UTERIKE EGG AT MOMENT 

 OF FERTUZATION 



SWOLLEN LAYERS OF JELLV 



MATURATION AND FERTILIZATION OF THE FROG'S EGG 



Growth period of egg and development of vitelline membrane — May to September. 

 Hibernation period, no changes -- October to March. 



Breakdown of germinal vesicle - at time of ovulation j 



Natural in March & April 

 Induced September to March 



Elimination of first polar body - during transit through oviduct (jelly applied from 

 oviduct). 



Second maturation to metaphase stage - in uterus, and until fertilization or death. 



Elimination of second polar body - 15-30 minutes after insemination. 

 Jelly swells rapidly when egg is placed in water. 



Fusion of pronuclei - 1-1/2 - 2 hours after insemination. 



First cleavage - 2-1/2 hours after insemination. 



