Genus: Pseudostome lacks lobed collar; test round or oval in cross-section; pseudostome at end of bent neck; test more or less coiled or folded (Illustrated Guide, 1985). Species: 95-190 μm long, 75-150 μm wide, 50-100 μm deep; test like flask, neck against body; with secreted imbedded siliceous particles; pseudostome circular 30-50 μm diam. QuickTime Movies http://protist.i.hosei.ac.jp/

50 μm 100 μm 150 μm; x 400 : 31 μm 63 μm 94 μm; x 640

Lesquereusia spiralis (Ehrenberg, 1840): 95-190 μm long, 75-150 μm wide, 50-100 μm deep; test like flask, neck against body; with secreted imbedded siliceous particles; pseudostome circular 30-50 μm diam.