Centropyxis hemisphaerica  (Barnard, 1875) Deflandre, 1929

Diagnosis: Shell large, dark brown, densely covered with xenosomes, in ventral view circular, in lateral view hemispherical; test narrowed in the apertural area; aperture circular, often irregular in shape, located eccentrically at the bottom of a small funnel. Shell with 6-16 long, usually curved spines.

Dimensions: Diameter of the test without spines 140-160 μm, height 85-106 μm, length of the spines 20-42 μm.

Habitat: Freshwater

Remarks: Barnard (1875) describes this species as follows: Shell hemisphaerical, depressed; tubules (3-7), more or less elongated and crooked, with large distal openings; the main aperture subcentral. This form occurs also on the muddy and dansy bottoms of ponds and creeks in New York. The irregular or variable number of tubules is probably due to the fact that sometimes one or more becomes accidently broken off.

Wailes (1913) described this species as C. aculeata var. hemisphaerica, Deflandre (1929) raised it to species level.