FACTS 



219 



which is adherent to it. During this time the male cytoplasm, 

 localized in a very small region called the spermo-centre 

 (Fig. 17), exercises its attraction on all the corresponding 

 elements of the female cytoplasm, tracing in its substance 

 radiating streaks which produce the figure called aster. 



The movement of the male pronucleus toward the female 

 pronucleus, . on the one hand, and the formation of the 

 cytoplasmic aster around the spermo-centre, on the other, 

 show there is reciprocal attraction of the pronuclei among 

 themselves and of the cytoplasms among themselves. There 

 is, therefore a nucleary fecundation and a cytoplasmic 

 fecundation, which proves that the diagram in Fig. 18 is 



i 



A 



FIG. 19. SEA URCHIN'S SPERMATOZOID ENTERING OVULE. 



exact, for the two fecundations show that maturation is 

 at once intranuclear and intra-cytoplasmic, or, in one word, 

 intraprotoplasmic . 



We need not insist further on figured phenomena of 

 fecundation. From our point of view their interest consists 

 in showing with evidence that bipolarity is a phenomenon 

 of smaller order than cellular magnitude. In other words, 



