TESTA CEA 243 



vacuoles; cytoplasm colorless, but occasionally with Zoochlorel- 

 lae. Several filopodia, branching. Test 115 to 170 microns 

 long by 70 to 100 microns wide. In sphagnum. 



Genus Assulina Ehrenberg. Test brown or colorless, ovoid, 

 compressed, with elliptical scales, arranged in diagonal rows. 

 Aperture oval, terminal, bordered by a thin chitinous dentate 

 membrane. A single nucleus is located posteriorly; contractile 

 vacuoles. Several filopodia, divergent, sometimes branched. 



Assulina seminuliim (Ehrenberg) (Fig. 97, c). Protoplasm 

 not completely filling up the test, with numerous food particles; 

 one contractile vacuole. Pseudopodia few, straight, divergent, 

 slender, seldom branched. Test 60 to 150 microns long by 50 to 

 75 microns broad. In mosses. 



Genus Nebela Leidy. Test thin, ovate or pyriform; com- 

 pressed, with circular or oval plates or discs of uniform or 

 various size; highly irregular. The endoplasm with oil-globules; 

 a single nucleus posterior. The protoplasm does not fill the test 

 and is connected with the latter by numerous ectoplasmic 

 strands at the fundus end. Pseudopodia blunt, rarely branched. 

 Numerous species. 



Nebela collaris (Ehrenberg) (Fig. 97, d). Test pyriform, 

 fundus obtuse in profile, aperture without any notch. The 

 endoplasm contains chlorophyllous food particles. Pseudopodia 

 digitate, short, usually 3 to 6 in number. Test 130 microns long 

 by 85 to 90 microns broad. In marshes among sphagnum. 



Genus Quadrula Schulze. Test pyriform, hemi-spherical, or 

 discoidal, consisting of a homogeneous chitinous film, with 

 quadrangular silicious or calcareous plates, arranged generally 

 in oblique series, not overlapping. A single nucleus. The body 

 and pseudopodia similar to those of Difflugia. Fresh water. 



Quadrula symmetrica (Wallich) (Fig. 97, e). Compressed, 

 smaller plates near the aperture. The cytoplasm very clear, 

 containing chlorophyllous granules. Three to five pseudopodia 

 digitate. A single nucleus posterior. Test about 95 microns 

 long by 60 to 70 microns broad. In sphagnum and other mosses. 



References 



Cash, J. 1905, 1909 The British freshwater Rhizopoda and 

 Heliozoa. Vols. 1, 2. 



