Limatula morioria n. sp. (Fig. 35.)

Shell of moderate size, oval, inflated, equilateral, beaks broad, ears inconspicuous. Sculpture of 29 sharp ribs with wide concave interspaces the central ribs are strong and erect the pair on each side of the median line rather closer together, the lateral ribs are low and oblique but well spaced; sharp close concentric ridges cross the interstices and surmount the ribs rendering their edge dentate. Valve-margin crenulated.

Height 18 mm.; length 12 mm.; thickness (1 valve) 6 mm.

Localities: Momoe-a-toa (type); Whenuataru Peninsula; Flowerpot.

Remarks: Distinguished from L. maoria Fin., by the less attenuated shape and persistence of the broad ribbing along the sides. There is no trace of the fine crowded anterior and posterior ribs of L. maoria.