Diagnosis. Cylindrical borings in shells, arcuate tu highly sinuous or planispiral, with thin, short, tapering side-branches at points where tubes abruptly change directions.

Description: Flint rock chip incompletely preserving external mold of a broad, finely punctate, smooth-shelled pedicle valve. Sinuous boring preserved in flint. Tunnels of boring cylindrical, of constant diameter, unsculptured. At tight bends in main shaft, short, slender and blunt side branches are developed, commonly in clusters. Main tunnel bifurcates once, branching Y-shaped (Fig. 1, 10 o’clock from center, branching toward 2-3 o’clock). Main tunnel strongly curved back on itself to touch in one position only; sides of touching tunnel may be slightly flattened (Fig. 1, center).