348 PROTOZOOLOGY 



temporary anterior region; posterior reigon with nipple-like projec- 

 tions; a small number of striae become visible during movement, 

 showing there is a very thin pellicle; endoplasm always vacuolated, 

 the vacuoles varying in size (up to 30m in diameter) ; vesicular nucleus 

 with an endosome; 50-125^ long during locomotion; fresh w^ater. 



A. vespertilio Penard (Fig. 162, b, c.) Pseudo podia conical, com- 

 paratively short, connected at base by web-like expansions of ecto- 

 plasm; endoplasm colorless, with numerous granules and food par- 

 ticles; a single vesicular nucleus with a large endosome; contractile 

 vacuoles; 60-100)u long; fresh water. 



A. gorgonia P. (Fig. 162, d-f). Body globular when inactive with 

 a variable number of radiating 'arms,' formed on all sides; locomotion 

 by forming elongate pseudopodia, composed of both ectoplasm 

 and endoplasm; nucleus, vesicular, with a large endosome; 40-50/i 

 in diameter; extended forms about 100^ long; fresh water among 

 vegetation. 



A. radiosa Ehrenberg (Fig. 162, g). Small, usually inactive; 

 globular or oval in outline; with 3-10 radiating slender pseudopodia 

 which vary in length and degree of rigidity; when pseudopods are 

 withdrawn, the organism may be similar to A. proteus in general ap- 

 pearance; pseudopods straight, curved or spirally coiled; size varies, 

 usually about 30m in diameter, up to 120)U or more; fresh water. 



Genus Dinamoeba Leidy. Essentially Amoeba, but the temporary 

 posterior region of body with retractile papillae; body surface includ- 

 ing pseudopods and papillae, bristling with minute spicules or mo- 

 tionless cils; often surrounded by a thick layer of delicate hyaline 

 jelly, even during locomotion; fresh water. 



D. mirahilis L. (Fig. 162, h). Oval to limaciform; spheroid when 

 floating; pseudopodia numerous, conical; ectoplasm clear, usually 

 with cils; endoplasm with food vacuoles, oil (?) spherules and large 

 clear globules; nucleus and contractile vacuole obscure; spherical 

 forms 64-160/i in diameter; creeping forms 152-340)uby 60-220^; in 

 sphagnous swamp. 



Genus Pelomyxa Greeff. Large amoeboid organisms, ranging from 

 0.5 to 4 or 5 mm. in length when clavate and moving progressively; 

 nuclei numerous, 100 to 1000 or more; many small contractile vacu- 

 oles; refringent bodies ("Glanzkorper") of various dimension and 

 amount; wdth or without bacterial inclusions (which Penard and 

 others consider as symbiotic) ; holozoic on plant or animal organisms; 

 plasmotomy into 2 or more individuals; all in fresh water. Several 

 species. 



P. palustris G. (Fig. 163, a). Large; 2-3 mm. or larger in diameter; 



