48 



PROTOZOOLOGY 



etc., walk on frontals, ventrals, and anals, while swimming move- 

 ment by other species is of different types. 



In all euciliates except Holotricha, there are adoral membranel- 

 lae. A membranella is composed of a double ciliary lamella, fused 

 completely into a plate (Fig. 12). A number of these membranel- 

 lae occur on a margin of the peristome, forming the adoral zone 



Fig. 10. Diagrams of cilia (Klein), a, Coleps; b, Cyclidium glaucoma; 

 c, Colpidiu7n colpoda. af, axial filament; bg, basal granule; of, circular 

 fibril; cs, cross-striation; sg, secondary granule. 



of membranellae, which serves for bringing the food particles to 

 the cytostome. The frontal portion of the zone, the so-called 

 frontal membrane, appears to serve for locomotion and Kahl 

 considers that it is probably made up of three lamellae. The 

 membranes which are often found in Holotricha and Hetero- 

 tricha, are transparent thin membranous structures composed of 

 one or two rows of cilia, which are more or less strongly fused. 



