PLATE XL. 



Figures 33-35 magnified 200 ilia meters ; figure 36 magnified 485 diameters. 



page 



Fig. 33. Spirostomum teres C. & L 162 



Fig. 34. Stentor roeselii Ehr 163 



Fig. 35. Spirostomum ambiguum Ehr ' 161 



Fig. 36. Halteria grandinella Mull 163 



