CILIATE PROTOZOA (INFUSORIA) 



277 



57 (58) Body purse-shaped Phascolodon Stein. 



58 (57) Body ovate or nearly spherical iri outline with a slight lip at the 



anterior end. Mouth at the base of the lip with no evident 



pharynx. Cilia ventral in six rows. . . . Hexotricha Conn. 



Representative species Hexotricha globosa Conn 1905. 



FIG. 483. Hexotricha globosa. Lateral and end views, cv, contractile 

 vacuole; m, mouth, x 335. (After Conn.) 



59 (4) Usually with an undulating membrane or membranes about the mouth. 



Mouth always open. . . . Suborder Trichostomina . . 60 



60 (87) Peristome usually absent; wither without undulating membranes. 61 



61 (70) Without an undulating membrane; pharynx present 62 



62 (65) One or two broad zones of strong cilia about the body; with a tail- 



like tuft of cilia 63 



63 (64) Two broad zones of strong cilia about the body. Body cylindrical, 



with mouth posterior leading into a short pharynx. An- 

 terior part of the body uniformly ciliated. A band of 

 strong cilia near the middle and posterior end. 



Urocentrum Nitzsch. 

 Representative species Urocentrum turbo Miiller 1786. 



Body broadly rounded anteriorly, rounded or truncate posteriorly. 

 Movement by a rotation on the long axis or swiftly darting from side 

 to side. Contractile vacuole posterior with the band-like nucleus 

 curved about it. Length 100 /* Pond water. 



FIG. 484. Urocentrum turbo, cv, contractile vacuole; n, nucleus. X 200. 

 (After Kent.) 



64 (63) With an oblique circle of strong cilia near the anterior end. Body 

 somewhat pyriform, rigid, finely ciliated. Two groove-like 

 canals encircling the body. Mouth ventral, posterior to 

 the grooves and leading into a short pharynx. 



Calceolus Diesing. 

 Representative species. . . Calceolus cypripedium James-Clark 1866. 



Color light brown. Very similar in movement to Urocentrum turbo. 

 Length 80 to 160 /a. Fresh water. 



FIG. 485. Calceolus cypripedium. cv, contractile vacuole; macn, macronucleus, 

 X 200. (After Kent.) 



