AMOEBINA 437 



Family 2 Amoebidae Bronn 



These amoebae do not have flagellate stage and are exclusively 

 amoeboid (monophasic) . They are free-living in fresh or salt water, 

 in damp soil, moss, etc., and a few parasitic; 1, 2, or many nuclei; 

 contractile vacuoles in freshwater forms; multiplication by binary 

 or multiple fission or plasmotomy: encystment common. Genera 

 (Leidy, 1879; Penard, 1902; Singh, 1952). 



Genus Amoeba Ehrenberg (Proteus Miiller; Amiba Bory). Amoe- 

 boid; a vesicular nucleus, either with many spherical granules or with 

 a conspicuous endosome; usually one contractile vacuole; pseudo- 

 podia are lobopodia, never anastomosing with one another; holozoic; 

 in fresh, brackish or salt water. Numerous species. Nomenclature 

 (SchaefTer, 1926; Mast and Johnson, 1931; Kudo, 1952). 



A. proteus (Pallas) (Figs. 2, e, f; 25; 33, b, c; 43,/; 45-47; 68; 184, 

 a, b). Up to 600m or longer in largest diameter; creeping with a few 

 large lobopodia, showing longitudinal ridges; ectoplasm and endo- 

 plasm usually distinctly differentiated; typically uninucleate; nu- 

 cleus discoidal but polymorphic; endoplasmic crystals truncate bi- 

 pyramid, up to 4.5m long (SchaefTer, 1916); nuclear and cytosomic 

 divisions show a distinct correlation (p. 169); fresh water. Cytology 

 (Mast, 1926; Mast and Doyle, 1935, 1935a) ; nuclear division (Chalk- 

 ley, 1936; Liesche, 1938). 



A. discoides SchaefTer (Figs. 43, g; 184, c). About 400m long during 

 locomotion; a few blunt, smooth pseudo podia; crystals abundant, 

 truncate bipyramidal, about 2.5m long (SchaefTer) ; endoplasm with 

 numerous coarse granules; fresh water. 



A. dubia S. (Figs. 43, h-l; 184, d). About 400m long; numerous 

 pseudo podia flattened and with smooth surface; crystals, few, 

 large, up to 30m long and of various forms among which at least 4 

 types are said to be distinct (SchaefTer); contractile vacuole one or 

 more; fresh water. Nuclear division (Dawson et al., 1935); viscosity 

 (Angerer, 1942); contractile vacuole (Dawson, 1945). 



A. verrucosa Ehrenberg (Figs. 33, a, d-h; 44, a; 184, e). Ovoid in 

 general outline with wart-like expansions; body surface usually 

 wrinkled, with a definite pellicle; pseud opodia short, broad and 

 blunt, very slowly formed; nucleus ovoid, vesicular, with a large en- 

 dosome; contractile vacuole; up to 200m in diameter; fresh water 

 among algae. 



A. striata Penard (Fig. 184,/). Somewhat similar to A. verrucosa, 

 but small; body flattened; ovoid, narrowed and rounded posteriorly; 

 nucleus vesicular; contractile vacuole comparatively large and often 



