Fig. 26 Diagrammatic representation of conjugation in Paramecium cau- 

 datum. X about 130. (After Calkins), 

 a-f, micronuclear divisions; g, exchange of micronuclear material; h, fer- 

 tilization; i-n, stages in three successive divisions of the nucleus; o, differentia- 

 tion of four macronuclei and micronuclei; p, one of the products of the first 

 cytoplasmic division, containing two macronuclei and two micronuclei; q, the 

 products of the second and last cytoplasmic division, each possessing one mac- 

 ronucleus and one micronucleus; r, nuclear fusion such as shown in h, under 

 higher magnification (X1200 after Dehorne). 



[541 



