PROTOZOA IN GENERAL 



81 



Among the plantlike types are several of interest, including Uroglena, 

 found in reservoirs and imparting a peculiar oily odor and fishy taste to 

 the water. Another form is Volvox, a very beautiful colonial animal — 

 or plant — which lives in fresh water and which may consist of many 

 thousands of cells. As it swims the spherical colony revolves, the motion 



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Fig. 31. — Different types of Sarcodina. A, Rotalia freyeri. {From Doflein, " Lehrbuch 

 der Protozoenkunde," after Max Schultze, by the courtesy of Gustav Fischer.) An example 

 of the Foraminifera. B, Difflugia urceolata Carter. {From Leidy, "Fresh-water Rhizopods 

 of North America.") X 167. The shell is composed of sand grains. C, Actinosphaerium 

 eichhorni Ehrenberg. {From Kudo, "Handbook of Protozoology," by permission of the 

 publisher, Charles C. Thomas.) X 40. One of the Heliozoa. D, Heliosphaera inermis 

 Haeckel. {From Bronn, " Klassen und Ordnungen des Tierreicha," after Haeckel.) X 350. 

 One of the Radiolaria. The skeleton forms a lattice work on the surface of the body. 



being due to the combined action of all the flagella. Still another example 

 is a marine form known as Nocfiluca. This animal frequently collects 

 on the surface of the sea in enormous numbers, the jelly-hke bodies form- 

 ing a thick scum which has the color and appearance of thick cream-of- 

 tomato soup and which sometimes covers an area of many acres. At 



