M--^t^ A 



<^prorv 



Fig. 62. — The Maturation and Impregnation of ihe Animal Ovum. 



A, the ovum, surrounded by the vitelline membrane {iiion), in the 

 act of forming the first polar cell {pol) : $ cent, centrosome. 



B, both polar cells (pol) are formed, the female pronucleus ( ? pron) 

 lies near the centre of the ovum, and one of several sperms is shown 

 making its way into the ovum at the micropyle [mkrop). 



