CONJUGATION OF CILIATA. 



203 



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

 Oxytrichina, Ckilodon, by their sides; while Enchclys, JIaltcria, 

 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, Tric/todina, etc., 

 between individuals 

 of unequal size, the 

 smaller one having 

 the appearance of a 

 bud (bud-like conju- 

 gation) (fig. 143, c). 



The alterations 

 which the nucleus 

 and paranucleus un- 

 dergo during and 

 after conjugation have been especially worked out in Paramcecium and 

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



FlG. 144. a, Stylonychia mytiliis, in process of conjugation. 

 The nucleus is depicted i uving division (Balbiani's so- 

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

 posed spermcapsules). b, Stylonychia filled with parasitic 

 Spfitfroj>>irya (after Balbiani). 



FIG. 14S,Stylonyeh!a myfllus in process of conjugation, slightly magnified, (treated with 

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

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

 tion with four nucleoli, of these N' becomes the nucleus, and ' the two nucleoli ; Jfb, tho 

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

 tion with nucleus and two nucleoli. 



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

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



