Neithea texana

The shell is medium to large, subtrigonal, subequilateral solid; its height exceeding length only slightly; its postero-dorsal margin is distinctly longer than antero-dorsal margin; its ventral margin is semi-circular with six projections formed by the extensions of the six raised ribs of the right valve.  The ears are large and hinge line straight.  Most of these specimens have been somewhat compressed.  These are found in the Georgetown Limestone, Austin, Texas.