308 PROTOZOOLOGY 



not s])lH'rical; extrcmoly delicate pellicle shows 3 or 4 fine longi- 

 tudinal lines which appear and disappear with the movement of 

 the body; 25-45iu by 20-35//; fresh water among vegetation. 



.4. guttula Diijardin (Fig. 140, g). Ovoid during locomotion, 

 narrowed behind; often with a few minute, nipple-like dentations 

 at the temporary posterior end; movement by wave-like expan- 

 sions of ectoplasm; endoplasm granulated, with crystals; a single 

 contractile vacuole; 30-35m by 20-25^; fresh water in vegetation. 



A. limicola Rhumbler (Fig. 140, h). Somewhat similar to A. 

 guttula; body more rounded; locomotion by eruption of cyto- 

 plasm through the body surface; 45-55/^ by 35/^; fresh water 

 among vegetation. 



A. spumosa Gruber (Fig. 141, a). Somewhat fan-shaped; flat- 

 tened; during locomotion broad pseudopodia with pointed end 

 at temporary anterior region; posterior region with nipple-like 

 projections; a small number of striae become visible during 

 movement, showing there is a very thin pellicle; endoplasm al- 

 ways vacuolated, the vacuoles varying in size (up to SO/j. in di- 

 ameter) ; vesicular nucleus with an endosome; 50 125^1 long during 

 locomotion; fresh water. 



A. vespertilio Penard (Fig. 141, h, c). Pseudopodia conical, com- 

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

 ectoplasm ; endoplasm colorless, with numerous granules and food 

 particles ; a single nucleus with a large endosome ; contractile vac- 

 uoles; 60-100^1 long; fresh water. 



A. gorgonia P. (Fig. 141, 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; 40-50/i in diameter; extended forms 

 about 100// long; fresh water among vegetation. 



A. radiosa Ehrenberg (Fig. 141, g). Small, usually inactive; 

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

 podia which vary in length and degree of rigidity; when pseudo- 

 pods are withdrawn, the organism may be similar to A. proteus 

 in general appearance; pseudopods straight, curved or spirally 

 coiled; size varies, usually about 30/i in diameter, up to 120/x or 

 more; fresh water. 



Genus Dinamoeba Leidy. Essentially Amoeba, but the tempo- 

 rary posterior region of body with retractile papillae; body sur- 

 face including pseudopods and papillae, bristling with minute 



