General Morphology of the Protozoa 29 



/o ) 



■^ 





/ 



u--- 



L.'^ A 



Fig. 1. 15. A. Section across the peristome of Oxytriclia jallax; xl225 

 (after Lund). B. Section through the middle of the peristome in Euplotes 

 aediculatus; x445 (after Pierson). C. Gullet-like structure in Amoeba iuve- 

 nalis after ingestion of a flagellate; diagrammatic (after Ivanic). D. Pharyn- 

 geal-basket in Chilodonella labiata; diagrammatic (after MacDougall). E, F. 

 Gullet-like structures in Dientamoeba fragilis; xl930 (after Wenrich). G. 

 Gullet (peristomial area) in Paramecium midtimicronucleatiim; diagram- 

 matic; x670 (after Linid). H. Peristome of Stylonychia; diagrammatic; x720 

 (after Lund). Key: b, pharvngeal-ljasket; c, cirrus; d, dorsal cilia; f, postoe- 

 sophageal fibrils; g, basal granule of cilium; m, row of membranelles; p, 

 basal granules of penniculus; u, undulating membrane; v, food vacuole; vd, 

 developing food vacuole. 



as a scoop which directs water toward the cytostome. The cytostome and 

 associated structures in Paramecium thus form an efficient mechanism for 

 concentrating small particles and delivering them to the food vacuole. 

 In Oxytricha (146) and Stylonychia (147) the left margin of the peri- 

 stome bears a row of adoral membranelles, while an undulating mem- 

 brane extends along much of the right peristomial wall (Fig. 1. 15, A, 



