152 



THE PROTOZOA 



FIG. 77. Diagram showing the successive stages of conjugation in Infusoria. 

 A, The two conjugants attached, each with a macronucleus (N) and a micro- 

 nucleus (n) ; B, C, the micronucleus of each conjugant dividing ; D, each 

 conjugant has two micronuclei which are beginning to divide again ; E, each 

 conjugant has four micronuclei ; the macronuclei are beginning to become 

 irregular in form ; in later stages they degenerate, break up, and are absorbed ; 

 F, three of the four micronuclei of each conjugant are degenerating and 

 being absorbed ; the fourth is dividing ; G, one half of each dividing micro- 

 nucleus of the preceding stage has travelled over into the other conjugant 

 as the migratory pronucleus ; H, I, fusion of the stationary pronucleus of each 

 conjugant with the migratory pronucleus derived from the other conjugant 

 to form the synkaryon (S.) ; J, the two conjugants now separate ; in each 

 ex-con jugant the synkaryon (S.) divides ; the old macronuclei are now almost 

 completely absorbed ; K, L, the synkaryon has divided into two nuclei, one 

 of which grows large and becomes the new macronucleus, the other remains 

 small and becomes the new micronucleus, of each ex-conjugant. After Delage 

 and Herouard. 



