AMOEBINA 



441 



P. palustris G. (P. villosa Leidy) (Fig. 186, a). Large; 2-3 mm. or 

 larger in diameter; sluggish, with usually one broad pseudopodium; 

 undifferentiated cytoplasm with many nuclei and various inclusions 

 such as fragments of plant bodies, numerous small sand particles, 

 etc., which brings about opacity and dark coloration of body; in 

 addition bacteria (Cladothrix pelomyxae Veley, Myxococcus pelomyxae 

 Keller and Bacterium parapelomyxae Keller) occur in the cytoplasm 



Fig. 186. a, Pelomyxa palustris, X160 (Leidy); b, c, P. carolinensis, 

 X45 (Kudo) (b, an individual in locomotion; c, feeding form); d, e, 

 P. illinoisensis, X40 (Kudo) (d, an individual in locomotion; e, a more 

 or less stationary animal); f, Vahlkampfia patuxent, X660 (Hogue); g, h, 

 Acanthamoeba castellanii, X1270 (Hewitt); i, j, A. hyalina, X840 (Do- 

 bell). 



which some observers consider as symbionts; cyst with two to three 

 envelopes (Stole, see Kudo, 1951) ; feeds on plant and inorganic de- 

 bris; polysaprobic in still stagnant water, buried in mud. Central 

 Europe, Great Britain and North America. Morphology (Greeff, 

 1874; Hollande, 1945); locomotion (Okada, 1930a; Mast, 1934); 

 plasmogamy (Okada, 1930) ; laboratory cultivation (Hollande, 1945). 



