TESTACEA 327 



less; aperture elastic, terminal; colorless cytoplasm fills the test; 

 large nucleus posterior; numerous filopodia long, branching, not 

 anastomosing; fresh water. 



L. hyalinum (Ehrenberg) (Fig. 149, c). Spheroidal; aperture 

 circular with a short flexible neck; a single contractile vacuole; 

 diameter 20-45yu; in submerged vegetation. 



Genus Schultzella Rhumbler. Test thin, delicate, difficult to 

 recognize in life, easily broken at any point for formation of pseu- 

 dopodia which branch and anastomose; irregularly rounded; 

 without foreign material; salt water. 



S. diffluens (Grubler) (Fig. 148, g). Cytoplasm finely granu- 

 lated; opaque colorless; with oil droplets, vacuoles and numerous 

 small nuclei; up to 220/^ in diameter. 



Genus Myxotheca Schaudinn. Amoeboid; spherical or hemi- 

 spherical, being flattened on the attached surface; a thin pseudo- 

 chitinous test with foreign bodies, especially sand grains; pseu- 

 dopodia anastomosing; salt water. 



M. arenilega S. (Fig. 149, d). Test yellow, with loosely attached 

 foreign bodies; cytoplasm bright red due to the presence of highly 

 refractile granules; 1-2 nuclei, 39-75^ in diameter; body diame- 

 ter 160-560iu. 



Genus Dactylosaccus Rhumbler. Test sausage-shape and vari- 

 ously twisted; pseudopodia filiform, anastomosing; salt water. 



D. vermiformis R. (Fig. 149, e). Test smooth; pseudopodia arise 

 from small finger-like projections; 1-2 nuclei; body 4 mm. by 

 340ju; salt water. 



Genus Boderia Wright. Body form changeable; often spherical, 

 but usually flattened and angular; filopodia long; test extremely 

 delicate, colorless; salt water. 



B. turneri W. (Fig. 149,/). Body brown to orange; active cyto- 

 plasmic movement; 1-10 nuclei; multiple division (?); 1.56-6.25 

 mm. in diameter; in shallow water. 



Family 2 Arcellidae Schultze 



Genus Arcella Ehrenberg. Test transparent, chitinous, densely 

 punctated; colorless to brown (when old); in front view circular, 

 angular, or stellate; in profile plano-convex or hemispherical; 

 variously ornamented; aperture circular, central, inverted like a 

 funnel; protoplasmic body does not fill the test and connected 

 with the latter by many ectoplasmic strands; slender lobopodia, 



