MORPHOLOGY 



57 



bands of close-set cilia. In a number of forms, such as Coleps, Sten- 

 tor, etc., there occur, mingled among the vibratile cilia, immobile 

 stiff cilia which are apparently solely tactile in function. 



Fig. 10. a, cilia of Coleps; b, cilium of Cyclidium glaucoma; c, basal por- 

 tion of a cilium of Colpidium colpoda, all in silver preparations (Klein); d, 

 electronmicrograph of a dried cilium of Paramecium, shadow-cast with 

 chromium, XI 1,000 (Jakus and Hall). 



In the Hypotricha, the cilia are largely replaced by cirri, although 

 in some species both may occur. A cirrus is composed of a number of 

 cilia arranged in 2 to 3 rows that fused into one structure com- 

 pletely (Figs. 11, a; 12, a), which was demonstrated by Taylor. Klein 

 also showed by desiccation that each marginal cirrus of Stylonychia 



