REPRODUCTION 



157 



small mass cultures containing surplus animals from isolation 

 lines at 31°C. for 1-2 days. Endomixis has since been observed 

 more often in encysted stage of Spathidium spathula, Uroleptus 

 mobilis, Euplotes longipes, Didinium nasutum, etc. As to its sig- 

 nificance, the statement made for conjugation appears also to 

 hold true. 



In Paramecium aurelia, Diller (1936) found simple fragmenta- 











Fig. 78. Paedogamy in Actinophrys sol, X460 (Belaf). a, withdrawal 

 of axopodia; b, c, division into two uninucleate bodies, surrounded by 

 a common gelatinous envelope; d-f, the first reduction division; g-i, 

 the second reduction division; j-1, synkaryon formation. 



tion of the macronucleus which was not correlated with any 

 special micronuclear activity and which could not be stages in 

 conjugation or autogamy. Diller suggests that if conjugation or 

 autogamy is to create a new nuclear complex, as is generally 

 held, it is conceivable that somewhat the same result might be 

 achieved by 'purification act' (through fragmentation) on the 

 part of the macronucleus itself, without involving micronuclei. 

 He coined the term 'hemixis' to include these reorganizations. 

 Meiosis. In the foregoing sections, references have been made 



