REPRODUCTION 



129 



In the unique resting nucleus of Spirotrichonympha polygyra 

 (Fig. 58), Cleveland (1938) found four chromosomes, each of 

 which contains a distinct coil within a sheath and its one end con- 

 nected with the anterior margin of the nuclear membrane by an 





Fig. 58. Mitosis in Spirotrichonympha polygyra (Cleveland), a, 

 resting nucleus with 4 chromosomes; b, c, prophase; d, chromosomes 

 mo\ang apart; e, elongation of nucleus; f, telophase; g, a daughter 

 nucleus in which the chromosomes are splitting, a-e, X3800; f, g, 

 X2400. 



intranuclear chromosomal fiber, and the other with a deeply 

 staining endosome (a). The spindle fibers appear between the 

 separating flagellar bands which come in contact with the nuclear 

 membrane. Soon some of the astral rays become connected mth 

 the intranuclear chromosomal fibers and one long and one short 



