AMOEBINA 345 



T. philippinensis W. (Fig. 160, g-j). Amoeboid stage 16-18ju in 

 diameter; oval cysts 13-14ju by 8-12)u; flagellate stage 16-22/i by 



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. 



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

 boid; naked, in a few species there are indications that a delicate 

 pellicle occurs; a single nucleus, vesicular or somewhat compact; 

 contractile vacuoles; pseudopodia mainly lobopodia, never anas- 

 tomosing with one another; some students have used the nuclear 

 structure for specific differentiation, but unfortunately not always 

 clear; holozoic; fresh, brackish or salt water. Numerous species. 



A. proteus (Pallas) (Figs. 25; 32, h, c; 41,/; 43-45; 161, a, h). Up to 

 600;u or longer in largest diameter; creeping with a few large lobopo- 

 dia, showing longitudinal ridges; ectoplasm and endoplasm usually 

 distinctly differentiated; typically uninucleate; nucleus disco idal 

 but polymorphic; endoplasmic crystals truncate bipyramid, up to 

 4.5^1 long (Schaeffer); nuclear and cytosomic divisions show a dis- 

 tinct correlation (p. 143) ; fresh water. 



A. discoides Schaeffer (Figs, 41, g; 161, c). About 400^ long during 

 locomotion; a few blunt, smooth pseudopodia; crystals abundant, 

 truncate bipyramidal, about 2.5;u long (Schaeffer); endoplasm with 

 numerous coarse granules; fresh water. 



A. dubia S. (Figs. 41, h-l; 161, d). About 400m long; numerous 

 pseudopodia flattened and with smooth surface; crystals, few, 

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

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

 more; fresh water. Angerer (1942) studied the action of cupric chlo- 

 ride on the protoplasmic viscosity of this amoeba. 



A. verrucosa Ehrenberg (Figs. 32, a, d-h; 42, a; 161, e). Ovoid in 

 general outline with wart-like expansions; body surface usually 

 wrinkled, with a definite pellicle; pseudopodia short, broad and 

 blunt; nucleus ovoid, vesicular, with a large endosome; contractile 

 vacuole; up to 200m in diameter; fresh water among algae. 



A. striata Penard (Fig. 161,/). Somewhat similar to A. verrucosa, 

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

 nucleus vesicular; contractile vacuole comparatively large and often 



