Genus Perrierina Bernard, 1897.
Type: P. taxodonta Bernard.

Perrierina ovata n. sp. (Figs. 8, 9.)

Shell minute, ovate, equivalve, inequilateral. Beaks fairly prominent, with a well defined, rounded, projecting prodissoconch. Sculpture of crowded microscopic concentric threads. Hinge narrow, with central triangular or trapezoidal ligament-pit separating about 4 or 5 anterior and 4 or 5 posterior teeth, all horizontal and straight except a rounded or tubercular one on each side of the central pit. Valve-margins sometimes with a few indistinct crenations on the ventral margin, sometimes quite smooth.

Height 1.5 mm., length 1.7 mm., inflation .5 mm.

Locality: Titirangi, common.

Suter has put this genus in the Crassatellitidae; but conchologically, Perrierina has no resemblance to this family. The writer does not know of any other shell with a hinge like Perrierina and so proposes the new family Perrierinidae.