|  Genus: Pseudostome lacks lobed collar; test round or oval in cross-section; 
with or lacking a collar (Illustrated Guide, 1985). Species: Test pyriform, flask-shaped, or ovoid; neck variable in length; 
aperture terminal, typically circular; test composed of angular sand-grains, diatoms; 
60-580 μm by 40-240 μm (Kudo, 1966).
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