THEORY OF SEX— ITS NATURE AND ORIGIN. 



"3 



are quiescent forms, in which the life seems to sleep, and locomotion 

 is almost absent, — the gregarines, and some unicellular algae; and 

 between these there are forms which in a 

 via media have effected a sort of compromise 

 between activity and passivity, which are 

 without the celia of the one or the self-con- 

 tained stagnancy of the other, but possess 

 outflowings of their living substance, — the 

 familiar amoeboid processes. He would thus 

 reach, almost by inspection, a rough and 

 ready classification of the Protozoa, into 

 active, passive and amceboid cells, — a classi- 

 fication however which, under varying titles, 

 is more or less distinctly recognized by all 

 the authorities on the subject. 



But if he went further than casual inspec- 

 tion, and studied the life-history of some of 

 the very simplest forms, such as some of the 

 primitive molds or Myxomycetes, and followed 

 Haeckel's account of the life-cycle in Proto- 



myxa, he would gain new light on his classification. For in these life- 

 histories he would find the cells now encysted, now active lashed 

 spores, and again sinking down into the compromise of equilibrium 

 effected by amoebae. He is now in a position to recognize that the 



Fig. 32. — The divergence of male 

 and female cells from primitive 

 amoeboid indifference. 



Fig. 33. — The encysted Prototnyxa, and its division into numerous individuals within the cyst. 



— From Harckel. 



chapters in the life-history of the simplest forms are, as it were, proph- 

 ecies of each of his three groups. Before final differentiation has taken 

 place, the organisms pass through a cycle of phases, on eof whchi is 

 accented by each of the different groups of the Protozoa. Thus an 



