136 



SEX IN MICROORGANISMS 



Fig. a. 



1-12, diagrammatic life cycle of Ocbrosphaera iieopolitana (Coccolithophoridae) 

 from Schwarz (1932), redrawn. Non-motile stages predominate. 1, zygote; 2, four 

 cells resulting from meiotic divisions; 3, vegetative cell, derivable from a gamete or 

 zygote; 4-6, division of vegetative cell; 4a, 6a, escape of "zoospores"; 7-10, develop- 

 ment of gametocytes and gametes; 11, escape of gametes; 12, fusion of gametes. 13, 

 apparent fusion of protoplasts of two individuals of Chrysococciis spiralis, from 

 Lackey (1938), redrawn. 14, vegetative stage; 15, zygote of Cbrysolykos planktoniciis 

 with adhering loricae, from Mack (1951), redrawn. 



