THE EVOLUTION OF SEX 



25 



(see Fig. 4s), and others in which only sperms 

 are being produced (see Fig. 4c). The former 



FIG. 4s. A Volvox colony in a female phase, producing 

 numerous ova or egg-cells (E). (After Klein.) 



FIG. 4c. A Volvox colony in a male phase, producing clusters 

 of male-cells or spermatozoa (SP). (After Klein.) 



seem to be more vegetative and anabolic 

 than the latter ; we may begin to call them 

 female and male organisms respectively; for 



