232 



SEX IN MICROORGANISMS 



phusa, conjugation was preceded by an unequal division of an 

 ordinary individual into a larger macroconjugant and a smaller 

 "gametocyte," which then divided into two microconjugants. The 

 gametocyte was not ciliated, but the micronconjugants were. There 

 were two types of these with different ciliation and size. Only the 

 larger type was seen to function as a micronconjugant. The nuclear 

 phenomena were typical of the vorticellids. 



Fig. ah. 



1-4 from Dogiel (1925). 1-3, stages in Opisthotrichium jaims: 1, progamic division 

 producing unequal conjugants; 2, conjugation of macro- and microconjugants; 3, 

 conjugation of two macroconjugants; 4, conjugation of Cycloposthium bipahuatiim 

 showing differentiation of migratory pronucleus into a sperm with tail; 5-8, stages 

 in total fusion of conjugants of Spirochona gemviipara, from Plate (1886). (All illus- 

 trations redrawn.) 



