TESTACEA 



237 



or diatoms. Diameter 100 to 140 microns. In sphagnous swamp, 

 moss, and soil. 



Difflugia lobostoma Leidy (Fig. 95, d). Test ovoid to sub- 

 spherical. Aperture terminal; with 3 to 6 lobes. Test usually 

 composed of sand-grains and rarely with diatoms. The endo- 

 plasm is colorless or greenish. Diameter 80 to 120 microns. In 

 ponds, ditches, soil, and moss. 



Fig. 95 a. Difflugia oblonga. XlOO (After Cash). 



b. D. urceolata. XlOO (After Leidy). 



c. D. arcula. X125 (After Leidy). 



d. D. lobostoma. XlOO (After Leidy). 



e. D. constricta. X150 (After Cash). 



f. Centra pyxis aculeata. X 150 (After Cash). 



g. Cucurbitella mespiliformis. X 150 (After Wailes). 

 h. Plagiopyxis callida. X150 (After Wailes). 



i. Pontigulasia vas. X150 (After Cash), 



j. Phryganella acropodia. X 140 (After Cash), 



k. Bullinula indica. XlOO (After Wailes). 



1. Heleopera petricola. X 140 (After Cash). 



Difflugia constricta (Ehrenberg) (Fig. 95, e). Test laterally 

 ovoid, fundus more or less prolonged obliquely upward, rounded, 

 and simple or provided with spines. Soil forms are spineless. 

 Aperture antero-inferior, large, circular or oval and its edge 

 inverted. Test composed of quartz sand-grains. Colorless to 



