CONJUGATION OF CILIATA. 



203 



nected by their ventral surfaces ; other Inf usoria 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) (fig. 143, c). 



The alterations FIG. 144. a, Stylonychia myiihit, in process of conjugation. 



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



Which the nucleus called ova ). the nuc leoli have divided into four spheres (sup- 

 and IXlTCinucleus un- posed spermcapsules). 6,' Stylonychia filled with parasitic 



Sphatrophrya (after Balbiani). 



dergo during and 



after conjugation have been especially worked out in Paramcecium and 



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



FIG. 145. Stylonychia my fit us in process of conjugation, slightly magnified, (treated with 

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

 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 ; Nb, tho 

 lour 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 (Balbiani), the substance 

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



