182 



THE PROTOZOA 



G 



FIG. 81. General life-cycle of Trichosphcerium sieboldi, as an example of dimor- 

 phism in the adult condition combined with alternation of generations. 

 A, Schizont or non-sexual form, distinguished by the possession of rod-like 

 bodies in the envelope (compare F) ; this form may multiply by simple or 

 multiple fission (plasmotomy) in a " vegetative " manner, or by the process 

 of sporulation (schizogony ) seen in B and 0, in order to give rise to the gamete- 

 producing form ; B, division of the body of the schizont into as many cells 

 (" sporogonia ") as there are nuclei ; 0, rupture of the envelope and escape 

 of the sporogonia as active amcebulse, each of which forms an envelope for 



[Continued at foot of T . 183. 



