PLATE 3 



EXPLANATION OF FIGURES 



Ascending Phase (Except figures 31 to 34) 



25 Subculture IE, Line VIb, 4174th generation, January 18, 1914. Animal 

 after the first cell division. One macronuclear anlage. Some chromatin bodies 

 in process of disintegration and enclosed by vacuoles. One micronucleus has 

 divided and the other is in process of division for the ensuing cell division. 



26 Subculture IE, Line VI, 4185th generation, January 25, 1914. A charac- 

 teristic stage of the ascending phase of the process. New macronucleus with fine 

 chromatin granules. Two micronuclei present in cell but one near end omitted 

 from drawing. Chromatin bodies disintegrating. Cf. sister cells, text fig. 8. 



27 Subculture IE, Line Illb, 4313th generation, April 3, 1914. New macro- 

 nucleus, two micronuclei, four chromatin bodies and the cloud-like chromatin 

 remnants of the others. 



28 Main culture I, Line d, 1432 to 1433d generation, November 7, 1909. Young 

 animals just after division during the ascending phase of the process. Micro- 

 nuclei in each show various stages of division for the following cell division. 

 The. cell division just being completed is the fifth in about twenty-four hours 

 (see page 456). A few chromatin bodies still present. 



29 Subculture IE, Line VI, 4187th generation, February 27, 1914. New macro- 

 nucleus, two micronuclei and three chromatin bodies. 



30 Main culture I, Line b, 1201st generation, June 7, 1909. New macronu- 

 cleus, two micronuclei and two remaining chromatin bodies one of which is under 

 the macronucleus. 



31 Mass culture seeded from main Culture I. An epidemic of conjugation 

 in progress. Animal with micronuclei in process of division. 



32 Pair of conjugants, showing first micronuclear division after formation of 

 the syncaryon (cf. page 429 and page 453). 



33 An exconjugant from isolated conjugating pair. First vegetative division 

 completed. Macronuclear anlagen assuming typical macronuclear form. Note 

 finely granular condition of chromatin typical of new macronucleus. Two micro- 

 nuclei are present. Five food vacuoles with bacteria and promiscuous culture 

 material in which conjugation was secured. 



34 Paramaecium caudatum, Culture Y, Line 2, 139th generation, April 29, 

 1914. Descending phase of the process showing the formation of the chromatin 

 bodies in this species. The one characteristic micronucleus of caudatum has 

 divided Only optical section of micronuclei is drawn. 



512 



