Genus Cucurbitella Penard, 1902

 

Diagnosis: shell ovoid, with distinct apertural collar; outline regular, body constructed of small to medium, angular mineral grains. Organic cement seldom visible as surface structure. Collar with 3-12 lobes, composed of small mineral grains. Internal aperture a diaphragm with a circular or lobed opening on a level with main body wall. Nucleus vesicular. some species with zoochlorellae. 

 

 

Two Dutch species:

 

Diaphragm circular: Cucurbitella mespiliformis

 

Diaphragm three lobed: Cucurbitella vlasinensis