

.c 



I*'' 



V 



^~* ,..- 



^** x 



FIG. i. Dorsal aspect of specimen as seen when fixed to or creeping over host. 

 v, velum; c.v., contractile vacuole; f.v., food vacuoles; p.c., cilia of peristome; 

 m.n., meganucleus (U-shaped). Observe the small micronucleus lying at outer 

 margin of the U-shaped contour of meganucleus. X 1000. 



FIG. 2. Transverse optical section through diameter of striated horny ring or 

 ring band of adhesive organ, r.b., horny ring or striated ring band; d, denticles 

 or hooks. X 1000. 



FIG. 3. Free swimming Trichodina Steinii. p, peristome closed. Note posi- 

 tion of micronucleus and meganucleus with reference to the animal's swimming 

 posteriorly, as indicated by the arrow. 



FIG. 4. Free swimming form of Vorticella. Note position of micronucleus 

 and meganucleus with reference to the animal's swimming anteriorly, as indicated 

 by arrow. 



