PERITRICHA 



689 



V. picta (E.) (Fig. 323, q, r). 41-63^ by 20-37m; peristome 35-50m; 

 stalk 205-550/x by 4-7^; 2 contractile vacuoles; with refractile gran- 

 ules in stalk; fresh water. 



V. monilata Tatem (Fig. 323, s, t). Body with pellicular tuber- 

 cles; 2 contractile vacuoles; 50-78/1 by 35-57^; peristome 35-63/i 

 wide; stalk 50-200^ by 5-6. 5/x; fresh water. 



Genus Carchesium Ehrenberg. Similar to VorticeUa; but colonial; 

 myonemes in stalk not continuous, and therefore individual stalks 

 contract independently; attached to fresh or salt water animals or 

 plants; occasionally colonies up to 4 mm. high. Several species. 



Fig. 324. a, Carchesium polypinum, X200 (Stein); b, C. granulatum, 

 X220 (Kellicott); c, Zoothamnium arbuscula, X200 (Stein); d, Z. adamsi, 

 X150 (Stokes). 



C. polypinum (Linnaeus) (Figs. 35; 324, a). 100-125^ long; fresh 

 water. 



C. granulatum Kellicott (Fig. 324, 6). About 100/x long; 2 con- 

 tractile vacuoles anterior; on Cambarus and aquatic plants. 



Genus Zoothamnium Bory. Similar to Carchesium; but myonemes 

 (Fig. 15) of all stalks of a colony are continuous with one another, so 

 that the entire colony contracts or expands simultaneously; fresh 

 or salt water; colonies sometimes several millimeters high. Numerous 

 species. 



Z. arbuscula Ehrenberg (Fig. 324, c). 40-60^ long; colony up to 

 more than 6 mm. high; fresh water. 



Z. adamsi Stokes (Fig. 324, d). About 60/i long; colony about 250/x 

 high; attached to Cladophora. 



