162 



CLASS: RHIZOPODA 



diiced by altering tlie character of the medium in which the organisms 

 are growing. 



I '/w n\MX wv'■ 



Fig. 72. — Types of Shelled Riiizopoda. (From Lang, 1901, A and B, after 

 Max Schultze; C, after R. Hertwig. 



A. Gromia oviformis with ingested Navicula and seven nuclei ( x ca. 50). The 



pseudopodia round the shell should be three times as long as represented. 



B. Rotalia freyeri, showing spirally arranged chambers (x ca. 90). 



C. Spiroloculina sp., showing four chambers and nuclei (x ca. 30), 



In some instances {Mastig amoeba, Mastigina, Mastigella) the body 

 of the organism resembles an amoeba, in that pseudopodia are formed for 



