Genus Glycymeris da Costa, 1778.
Type: Arca glycymeris Linné.

Glycymeris traversi (Hutton).

1873. Pectunculus traversi Hutton, Cat. Tert. Moll. p. 28.

1914. Glycymeris traversi (Hutton): Suter, N.Z. Geol. Surv. Pal. Bull. 2, p. 35, pl. 4, figs. 2a, b.

1923. Glycymeris traversi (Hutton): Marwick, Trans. N.Z. Inst., vol. 54, p. 66, pl. 1, fig. 8.

Localities: Flower-pot Harbour, Pitt Island; Whenuataru Peninsula, Pitt Island.

Glycymeris laticostata (Quoy and Gaimard).

1835. Pectunculus laticostatus Q. and G., Voy. Astrol, vol. 3, p. 466, pl. 77, figs. 4–6.

1913. Glycymeris laticostata Q. and G.: Suter, Man. N.Z. Moll., p. 851, pl. 56, figs. 3, 3a.

Locality: Titirangi, a single damaged specimen.

Glycymeris hunti n. sp. (Figs. 7, 10.)

Shell of moderate size, light, obliquely oval, beaks narrow, some-what low. Sculpture consisting of fine regular radial threads, 5 per mm., superposed on a system of very low primary ribs which cannot be distinguished distally and so are of uncertain number; sometimes these ribs are slightly convex, but sometimes they are quite flat. Hinge-area somewhat narrow, teeth narrow, curved, about 15 anterior and 12 posterior without a median space; ligamental area narrow, with 6 striae about 0.5 mm. apart from each other. Valve-margin with about 50 fine crenulations the distal ones very small.

Height 35 mm.; length 40 mm.; thickness (1 valve) 10 mm.

Localities: Flower-pot Harbour. Pitt Island; Whenuataru Peninsula, Pitt Island; (?) Momoe-a-toa (cast).

This species closely resembles G. shrimptoni Marwick, but this is probably a convergence for the obliquity is present from a very early stage, the young being like G. modesta. In G. shrimptoni only some adults show obliquity, the young and many full grown ones being practically symmetrical.