Plate V. Electron micrographs of sections of compound cilia. 



(a) Transverse section through the base of a cirrus of Euplotes, 

 showing the regular arrangement of the cilia and their inter- 

 connections. The basal bodies are connected to each other 

 by fine filaments, and those at the edge of the cirrus are joined 

 to bundles of rootlet fibres which diverge to run in various 

 directions just beneath the body surface of the animal. From 

 Roth (1956). 24,000. 



(b) Transverse section through several cilia of a comb-plate 

 of Mnemiopsis. The cilia show an unusual arrangement 

 centrally, where a " mid-filament " is present between and to 

 the left of the normal central fibrils. Two of the peripheral 

 fibrils (numbers 3 and 8) are connected to the ciliary membrane 

 by " compartmenting lamellae " which terminate exactly 

 opposite similar lamellae of neighbouring cilia, and the lamellae 

 of adjacent cilia may be linked across the gap. The ciliary beat 

 is almost parallel with the longer side of the plate. From Afzelius 

 (1961a). X 155,000. 



