Early Miocene; Extinct.
Original Description (from Dall, 1900, p. 1022):
"Oligocene of the Chipola horizon at Alum Bluff and on the Chipola River, Calhoun County, Florida, and of the Oak Grove sands at Oak Grove, Santa Rosa County, Florida.
Shell small, inequivalve, inequilateral, plump, polished, the right valve flatter; anterior end longer, rounded, the posterior rather roundly pointed; base arcuate, near the posterior end a little concave; beaks small, pointed; posterior end obscurely rayed, slightly flexed; surface smooth or with incremental lines but no radial sculpture; anteriorly near the base are usually a few sparse, concentric, elevated threads with irregular but wider interspaces; the posterior dorsal area, contrary to the usual rule, is smooth and shows no traces of lamellation; hinge normal, rather feeble; a narrow impressed lunule; interior with some obscure radii; pallial sinus as in Angulus. Lon. 13.5, alt. 8.5, diam. 5 mm.
This species is on the border line between Angulus, Moerella, and Merisca. The right valve seems flatter, less arcuate below, and higher than the left when considered separately."
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