224 



SEX IN MICROORGANISMS 



Fig. AE. 



1-12, autogamy in Paramechmi aurelia, from Diller (1936); 13-22 "endomixis" in 

 P. caiidatum, from Chejfec (1930), all redrawn. 1, normal animal with two micro- 

 nuclei; 2, micronuclei in crescent stage; 3, second pregametic division, four nuclei 

 in metaphase; 4, eight products of second pregametic division, beginning resolution 

 of macronucleus; 5, six micronuclear products degenerate, two others divide; 6, 

 pronuclei in paroral cone, early skein of macronucleus; 7, fusion of pronuclei in 

 paroral cone, further resolution of macronucleus; 8, syncaryon in paroral cone; 9, 

 two products of division of syncaryon; 10, four products of second postzygotic 

 division; 11, two micronuclei and two anlagen; 12, products of first postzygotic cell 



