CONJUGATION OF CILIATA. 



203 



nected by their ventral surfaces ; other Infusoria with a flat body like 

 Oxytrichina, Chilodon, by their sides ; while Enchelys, Halteria, 

 Coleps, join together 

 the anterior extremi- 

 ties of their bodies, 

 giving the appear- 

 ance of transverse 

 fission. A lateral 

 conjugation also 

 takes place not un- 

 frequently in Vorti- 

 cella, Trichodina, etc., 

 between individuals 

 of unequal size, the 

 smaller one having 

 the appearance of a 

 bud (bud-like conju- 

 gation) (tig. 143, c). 



The alterations 

 which the nucleus 

 and paranudeus un- 

 dergo during and 

 after conjugation have been especially worked out in Paramcecium and 

 Stylonychia (fig 144 , 145). When several nuclei are present they 



a 



FIG. 144. a, Sfylonychia mytilus, in process of conjugation. 

 The nucleus is depicted c nriug division (Balbiani's so- 

 called ova); the nucleoli have divided into four spheres (sup- 

 posed spermcapsules) . 6, Stylonychia filled with parasitic 

 Sphcerophrya (after Balbiani). 



Nb 



FIG. 145. Stylonychia mytihtg in process of conjugation, slightly magnified, (treated with 

 acetic acid), (after Biitschli). , Stage of conjugation with two nucleoli (paranuclei) ; Nb, 

 the four pieces into which the nucleus has divided in each individual. 4, Stage of conjuga- 

 tion with four nucleoli, of these JV' becomes the nucleus, and ' the two nucleoli ; JV4, the 

 four remaining pieces of the old nucleus, c, Stylonychia on the sixth day after conjuga- 

 tion with nucleus and two nucleoli. 



fuse together to form a single oval body (Bulbiani), the substance 

 of which takes a finely fibrous structure previous to further fission, 



