86. Cilia fused into an undulatnig membrane along the groove leading to 



the mouth 87. 



No such membrane 88. 



87. Anterior end pointed, somewhat hooked; color commonly pink 



Blephansma Perty 

 Anterior end rounded; practically colorless 

 Metopus Claparede and Lachmann 



88. Anterior end asymmetrical, somewhat hooked; ventral surface concave 



Loxodes Ehrenberg 

 Anterior end rounded; animal cigar-shaped 

 Parameciurn Hill 



89. Anterior end of body narrovv'er than the posterior and usually somewhat 



asymmetrical 90. 



Animal almost evenly oval or with the anterior end slightly wider than 



the posterior 91. 



90. Body flattened sideways; no undulating membrane around the mouth 



Colpoda Miiller 

 Body scarcely flattened sideways; with an undulating membrane around 

 the mouth 



CoJpidium Stein 



91. Body lengthened, usually uncolored 



Frontoma Ehrenberg 

 Body ovate, usually red or brown 

 J^assula Ehrenberg 



GENERAL REFERENCES 



Calkins, G. N. 1926. The Biology of the Protozoa. Lea and Febiger. New 



York and Philadelphia. 

 Cash, J. and Hopkins, J. 1905-1909. The British Fresh-water Rhizopoda 



and Heliozoa. 2 vols. 

 Cash, J. and Wailes, G. H. 1915-1918. The British Fresh-water Rhizopoda 



and Helio-oa. Vols. 3 and 4. 

 Conn, H. W. 1905. The Protozoa of the Fresh Waters of Connecticut. State 



Geol. and Nat. Hist. Surv., Bull No. 2. 

 Edmondson, C. H. 1906. The Protozoa of Iowa. Proc. Davenport Acad. 



Sci., 11; 1-124. 

 Jahn, T. L. 1950. How to Know the Protozoa. Wm. C. Brown Co. Du- 

 buque, Iowa. 

 Kent, S. 1880-1882. A Manual of the Infusoria. 3 vols. London. 

 Kofoid, C. A. 1898-1899. Plankton Studies. Bull. 111. Nat. Hist. Surv., 5. 

 Kudo, R. R. 1946. Protozoology. 3rd Edition. C. C. Thomas. Springfield, 



111. 

 Lcidy, J. 1879. Fresh- water Rhizopods of North America. U. S. Geol. 



Surv. Territ. Vol. 12. 

 Stokes, A. C. 1888. A Preliminary Contribution toward a History of the 



Fresh-water Infusoria of the United States. Jour. Trenton Nat. Hist. 



Soc. Vol. 1. 

 Wenyon, C. M. 1926. Protozoology. London. 



47 



