Reproduction and Life-Cycles 



69 



always simple, however. A regular elimination of material (Fig. 2. 12) 

 from the macronucleus during division, or from the daughter nuclei 

 afterward, has been described in such genera as Ancistruma (142), Col- 

 poda (145), Tillina (14), Chilodonella (167), Colpidiinn, Glaucoma, and 

 Urocentnun (146). The significance of this process is unknown. 



Ciliates with more than one macronucleus and those with long beaded 

 or band-like macronuclei may show more complicated nuclear changes. 



Fig. 2. 11. A-D. Behavior of the endosome during mitosis in Heteronema 

 acus; A, B, D, x2890; C, x2270 (after Loefer). E. Intranuclear spindle, micro- 

 nucleus of Steutor coeruleus; x2365 (after Mulsow). F. Intranuclear spindle, 

 micronucleus of Stylonychia pustulata; xI730 (after IvaniC). G-I. Intra- 

 nuclear spindle in Oxymonas grandis; xl330 (after Cleveland). J-L. Intranu- 

 clear spindle in Pyrsonympha; early stage in development (J), x2920; later 

 stages (K, L), xl98r) (after Cleveland). 



