86 



Elementary Biology. 



nucleus, but each provided with a red spot of colouring- 

 matter and two fine flagella, by the constant vibration of 

 which they are able to move about with extreme rapidity. 

 The sperms are developed in the interior of club-shaped 



FIG. 24. SECTION OF THE CONCEPT ACLE OF Fucus platycarpus. (Thuret.) 

 f, 



a, b, sterile hairs ; c, ovaria ; e, spermaria ; d thallus. 



branches of the male hairs, each branch being a spermarium 

 (antheridium). Each spermarium consists at first of a cell- 

 wall and granular protoplasm, which latter gradually be- 

 comes segmented and modified into the sperms already 

 described, which escape on the rupture of the wall of the 



