HOLOTRICHA 619 



P. marinum D. (Fig. 292,/). Elongate ovoid ;tricho cysts distinct; 

 caudal cilia medium long; about 50 ciliary rows; 51-126m long 

 (Noland) ; in salt water; Florida. 



Genus Cyclidium Miiller. Small, 15-60m long; ovoid; usually 

 with refractile pellicle; with a caudal cilium; peristome near right 

 side; on its right edge occurs a membrane which forms a pocket 

 around cytostomal groove and on its left edge either free cilia or a 

 membrane which unites with that on right; no semicircular swelling 

 on left of oral region; round macronucleus with a micro nucleus; con- 

 tractile vacuole posterior; fresh or salt water. Numerous species. 



C. litomesum Stokes (Fig. 292, g). About 40/i long; dorsal surface 

 slightly convex with a depression in middle; ventral surface more or 

 less concave; cilia long; in fresh water. 



Genus Cristigera Roux. Similar to Cyclidium; much compressed; 

 with a postoral depression; peristome closer to mid-ventral line; 

 fresh or salt water. Several species. 



C. 'phoenix Penard (Fig. 292, h). 35-50^ long; fresh water. 



C. media Kahl (Fig. 292, i). 45-50^ long; in salt water. 



Genus Ctedoctema Stokes. Similar to Cyclidium in body form; 

 peristome nearer median line, diagonally right to left; right peri- 

 stomal ridge with a sail-like membrane which surrounds the cyto- 

 stome at its posterior end; trichocysts throughout; fresh water. 



C. acanthocrypta S. (Fig. 293, a). Ovoid; anterior end truncate; 

 macronucleus round, anterior; about 35/x long; in fresh water among 

 vegetation. 



Genus Calyptotricha Phillips. Somewhat resembles Pleuronema or 

 Cyclidium; but dwelling in a lorica which is opened at both ends; 

 with zoochlorellae; fresh water. 



C. pleuronemoides P. (Fig. 293, b). Lorica about 85/x high; body 

 about 50m long; Kellicott's (1885) form is more elongated; in fresh 

 water. 



Genus Histiobalantium Stokes. Ovoid; ventral side flattened; 

 ciliation uniform; long stiff cilia distributed over the body surface; 

 peristome deep; both anterior and posterior regions with a well- 

 developed membrane, connected with the undulating membrane; 

 macronucleus in 2 parts; 1-2 micro nuclei; several contractile vacu- 

 oles distributed; fresh water. 



H. natans (Claparede and Lachmann) (Fig. 293, c). 70-1 10m long. 

 H. semisetatum Noland (Fig. 293, d). Elongate ellipsoid ; posterior 

 end bluntly rounded; macronucleus spherical; longer cilia on pos- 

 terior half only; contractile vacuoles on dorsal side; 126-205^ long; 

 salt water; Florida. 



