COLLEGE ZOOLOGY 



Stentor (Fig. 43, A) may be either fixed or free swimming. 

 It is trumpet-shaped when attached and pear-shaped when 

 swimming. The cuticle is striated and just beneath it are 



FIG. 43. INFUSORIA. A, Stentor polymorphus of the order HETEROTRICHA. 

 B, Stylonychia mytilns of the order HY.POTRICHA. C, Vorticella of the order 

 PERITRICHA. D, Podophyra of the subclass SUCTORIA. c.vac, contractile 

 vacuole ; mg.nu, macronucleus ; mi.nu, micronucleus ; /, disc; 2, mouth; 

 3, peristomial groove; 4, vibratile membrane in mouth; 5, ectoplasm; 6, endo- 

 plasm ; 7, food vacuoles ; S, pharynx showing formation of food vacuoles ; 

 Q, contractile vacuoles; 10, permanent receptacle into which contractile vacuole 

 opens; //, micronucleus; 12, nucleus; 13, contractile fibrils running into 

 muscle in stalk; 14, stalk contracted (the axial fiber should touch the cuticle in 

 places). (A and B, from Weysse, after Kent; C, from Shipley and MacBride; 

 D, from Parker and Haswell.) 



muscle fibers (myonemes). The nucleus is ellipsoidal, or like 

 a row of beads. 



Order 3. Hypotricha (Fig. 43, B). -- CILIATA with a flattened 

 body and dorsal and ventral surfaces. The dorsal surface is free 



