Fig. 131. — Conjugation of Parametrium caudatum. \A-C, after R. HERTWJG; D-K t after 

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

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

 three polar bodies or " corpuscules de r6but," and one dividing germ-nucleus in each animal. D. 

 Interchange of the germ-nuclei. E. The same, enlarged. F. Fusion of the germ-nuclei. G. The 

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

 has divided twice, y. After three divisions of the cleavage-nucleus; the macronucleus is breaking 

 up. K. Four of the nuclei enlarging to form the new macronuclei. 



