REPRODUCTlo.X 



227 



uncommon. In Ciliata it is comparatively rare and limited appar- 

 ently to the Conotrichida and some parasitic forms. In Spirochona 

 (ic mini para according to Hertwig a swelling appears at one side of 

 the base of the peculiar funnel-like peristome. The nucleus divides 

 equally, one-half passing into the swelling which, with only partial 

 peristomial development, breaks away from 

 the parent and then completes its peri- 

 stomial differentiations. 



In Suctoria similar exogenous buds, 

 either single or multiple, are formed from 

 the oral extremity of the cell (Fig. 115). 

 Such buds are dissimilar to the parent 

 which they come to resemble only after a 

 period of metamorphosis and development. 



In Sporozoa, with the exception of some 

 Cnidosporidia, exogenous budding is lim- 

 ited to unequal division in gamete-forming 

 processes. Thus, in Gregarinida and in 

 microgametocytes of Coccidiomorpha the 

 nucleus of the cell undergoes several divis- 

 ions, the final products arranging themselves 

 about the periphery from which they be- 

 come nuclei of variously formed gametes 

 budded out from the surface (Fig. 173, 

 p. 403). In all such cases the parent 

 protoplasm dies after giving rise to the 

 buds. In some ( 'nidosporidia, on the other 

 hand, budding processes appear to be 

 normal activities carried on during the 

 vegetative life of the organisms. Accord- 

 ing to Cohn (1895) large numbers of buds, 

 each containing several nuclei, may be 

 formed from the periphery of Myxidium 

 lieberkilhni. The phenomenon appears to 

 be an exaggeration of the peculiar process 

 of division termed plasmotomy by Doflein, 

 whereby a multinucleated cell divides 

 spontaneously into two more or less equal 

 parts as in Chloromyxum leydigi accord- 

 ing to Liihe and Doflein, or into several parts, as in the Coccidian 

 Caryotropha mesnili and Klossiella maris and termed "schizonto- 

 cytes," or "cytomeres" by Siedlecki (1902). 



Terminal exogenous budding is characteristic of some parasitic 

 ciliates and a chain of posterior reproductive bodies is formed as 

 in Radiophrya limnodrili (Fig. 116). 



Fig. 



Radiop 



limnodrili, astomatous fili- 

 ate with terminal budding. 

 (After Cheissin, Archiv f. 



Protistenkunile, courtesy of 

 G. Fischer.) 



