98 



OUTLINES OF EVOLUTIONARY BIOLOGY 



be remembered, this is not so, certain cells only being concerned 

 in the sexual process. We have here a kind of fore-shadowing of 

 that distinction into somatic or body cells and sexual or germ 

 cells which is so characteristic of the higher organisms, both 

 plants and animals. We see a somewhat similar fore-shadowing 



FIG. 45. Fucua vesiculosus, about half nat. size. (From Vines' " Botaiiy.") 

 b, air bladders ; /, fertile branch. 



even in the unicellular Paramcecium, except that the distinction 

 is here confined to the nuclei, the meganucleus being concerned 

 with the life of the individual and the asexual process of ordinary 

 cell-division, while the micronucleus is alone concerned in the 

 sexual phenomena. We can, in this case, distinguish between 

 somatic nucleus and germ nucleus, though not between somatic 

 and germ cells. 



