Genus Lissarca Smith, 1877.
Type: L. rubrofusca Smith.

Lissarca fossilis n. sp. (Figs. 24, 25.)

Shell very small, oval, inflated, beaks small, close to anterior end. Surface apparently smooth except for a few strong spaced growth-lines. Hinge-plate arched, narrow, with four chevroned posterior taxodont teeth and about five nearly straight anterior ones, the two sets separated by a relatively large obliquely-triangular ligament-pit. Valve-margins with about three denticles, posteriorly anteriorly, and ventrally.

Height 3.2 mm.; length 3.7 mm.; thickness (1 valve) 1.5 mm.

Locality: Flower-pot Harbour, Pitt Island.

Resembles L. exilis Suter, but is larger, has no trace of radial sculpture and very few marginal crenulations.