AMOEBOID PROTOZOA (SARCODINA) 227 



90 (89) Shell ovoid; border of aperture crenulate. 



f?;^-^ Nebela dentistoma Penard 1890. 



The shell is very clear with round or oval plates, the arranRement of 

 the plates at the margin of the aperture forming the rounded crenu- 

 lations. Pseudopodia very active. Found in sphagnous swamps. 

 Length 66 to 130 a*. 



Fig. 316. Nebela dentistoma. x 160. (After Penard.) 



mm 



91 (84) Shell ovoid, compressed with round, oval, or irregular plates. . . 92 



92 (93) Aperture oval, terminating a short tube formed by the thickened 



oral membrane. Plates irregular. 



Awerinzewia Schouteden. 

 Representative species. . Awerinzewia cyclo^tomata ^choxxitdtn 1902. 



Shell a chitinous envelop covered by siliceous plates, some large, scatter- 

 ing, others small, filling in between the large ones. Sand grains often at- 

 tached to the posterior border. Color usually violet. Nucleus single. 

 Closely allied to the genus Heleopera. Length 135 to 1 78 m. Habitat mosses. 

 Fig. 317. Awerinzewia cyclostomata. X 100. (After Penard.) 



93 (92) Aperture elliptical or Hnear, not terminating a tube. 



Heleopera Leidy . . 94 



94 (95) Chlorophyl always present Heleopera picta Leidy 1874. 



The shell is very regular in outline, of a yellowish tint, 

 usually with little foreign material attached. The presence 

 of chlorophyl seems to be necessarj^ to the life of the animal. 

 Pseudopodia numerous. Found in sphagnous swamps. 

 Length 100 to iiom- 



Fig. 318. Heleopera picta. X 150. (After Leidy ) 



95 (94) Wine-red in color Heleopera rosea Penard 1890. 



This species may be known by its color, the tint being of variable 

 ^__^ ,_ depths. Sand grains and other foreign elements cover the fundus of 



%'^€.^^^^n the shell. A thin, yellowish lip borders the aperture. Found among 

 fe^^^^^^"^ mosses in swamps. Length 90 to 100 /i. 

 ~ ^ Fig. 319. Heleopera rosea. X 150. (After Penard.) 



96 (23) Pseudopodia sometimes thick, sometimes linear 97 



97 (100) Shell chitinous, densely covered with sand grains, diatom shells, and 



other foreign elements. . . . Phryganella Penard . . 98 



98 (99) Large size; foreign elements large, rough. 



Phryganella nidulus Penard 1902. 



The shell is hemispherical and usually oi rough contour. 

 Aperture large. Pseudopodia slender but often accompanied 

 by broad lobes of protoplasm. Found in the ooze of ponds 

 and lakes. Large forms are 200 n in diameter. 



Fig. 320. Phryganella nuiulus. x 90. (.\ftcr Penard.) 



