Fig. no. — Conjugation of Paramcecium caudatum. [A-C, after R. HertwiG; D-A', after 

 Maupas.] (The macronuclei dotted in all the figures.) 



A. Micronuclei preparing for their first division. B. Second division. C. Third division; 

 three polar bodies or " corpuscules de rebut," and one dividing germ-nucleus in each animal. D. 

 Exchange of the germ-nuclei. £. The same, enlarged. F. Fusion of the germ-nuclei. G. The 

 same, enlarged. //. Cleavage-nucleus, (c) preparing for the first division. /. The clfeavage- 

 nucleus has divided twice. Y- After three divisions of the cleavage-nucleus ; macronucleus 

 breaking up. A'. Four of the nuclei enlarging to form new macronuclei. Tlie first fission soon 

 takes place. 



o 225 



