leperditia

from The Century Dictionary.

• noun A genus of fossil ostra-code crustaceans, of the family Leperditiidæ, characterized by oblong unequal valves with straight dorsal edge and rounded ventral outline, overlappingventral edge of the right valve, eye-tubercle, and subcentral interior muscular imprint. The genus extends from the Lower Silurian to the Carboniferous.