Echinodiscus bisperforatus Leske, 1778

Fig. 62 A–D.

Echinodiscus bifora: Gray, 1825: 428 . Pl. XXVI.

Echinodiscus biforis: A. Agassiz, 1872: 113 .

Echinodiscus bisperforatus: Döderlein, 1910: 248; H.L. Clark, 1923: 394 –395; H.L. Clark, 1925a: 170; Mortensen, 1948d: 406 –411. Pl. LVIII, Figs 2, 6–8. Pl. LXXI, Figs 6–9, 18; Clark & Courtman-Stock, 1976: 243; Richmond, 1997: 300; Branch et al., 2010: 236, Fig. 106.8; Schultz, 2010: 341, Figs 645–646.

Material examined. MBC-A 022273; MBC-A 022273; MBC-A 022274; MBC-A 022276; MBC-A 022277; MBC- A 022296; MBC-A 022302; MBC-A 022275; MBC-A023310; MBC-A077907; MBC-A077904; MBC-A077908; MBC-A077909; MBC-A077905; MBC-A077906.

Identification. Test thin, fragile, highest point anterior of apical disc; apical disc with four gonopores; petals short; posteriorly truncated, two posterior slits; oral side with pressure drainage channels passing to anterior margin and to posterior slits; branching food grooves with distal side branches; spines aborally short, orally long. Live specimen uniformly purple, denuded test white.

Global maximum size. Maximum test length 118 mm.

Global distribution. Red Sea to South and East coasts of South Africa, Thailand, Malayan Archipelago and New Caledonia; from littoral to 50 m (Schultz 2010).

Remarks. Variation within species exists in the length of slits and in shape of posterior petals.