60 



Reproduction and Life-Cycles 



Colpidium, Glaucoma (49), and Stentor (238) retain the peristomial or- 

 ganelles. Division of the parental cytostome and peristome occurs in 

 CyclocJiaeta astropectinis (51) and possibly in other peritrichs. 



The infraciliature shows genetic continuity through multiplication of 

 basal granules, as traced in Chilodonella (49), Foettingeriidae (48), Opa- 

 lina (42), and Ichthyophthirius (71), among others. In Tetrahymena and 

 similar ciliates (Fig. 2. 4, G, H), the development of a new mouth for the 

 posterior daughter involves the multiplication of basal granules at a 

 particular level in the stomatogenous row. These basal granules later give 

 rise to membranelles of the new peristomial area. The continuity of basal 



Fig. 2. 4. A. Late fission in Opisthouecta heriueguyi, x410 (after Kofoid 

 and Rosenberg). B, C. Fission in Scyphidia ameiuri; ciliation not shown; 

 diagrammatic (after Thompson, Kirkegaard and Jahn). D-F. Fission in Cya- 

 thodiniuyn piriforme (after Lucas); two new sets of cilia move into the trans- 

 verse axis (D, E), and posterior ends of daughter organisms are separated in 

 fission (F); D, E, xl220; F, xll60. G, H. Fission in a hypothetical ciliate 

 similar to Tetrahymena; basal granules (indicated diagrammatically) multiply 

 in a particular region of the stomatogenous row (G) and liecome organized 

 into new adoral membranes (H). 



