Cassidae

Semicassis bisulcata

(Schubert & J. A. Wagner, 1829)

Shell 23 to 71 mm in length, ovate-globose, smooth or spirally striate, thin- or thick-shelled, with or without 5 or 6 spiral rows of reddish to yellowish brown, squarish spots, and with a rugose or spirally lirate columellar shield. A very variable species. Nuclear whorls bulimoid, slightly tilted, smooth, glossy, white or tan. Early postnuclear whorls with 4 to 7 small, beaded, irregularly-sized, spiral threads. Last two whorls usually smoothly rounded, but may be slightly shouldered due to 2 to 4 strong spiral cords be- low the impressed suture. Body whorl may be smooth or with numerous fine, incised lines, or with numerous crowded, coarse, spiral cords which may be smooth or weakly beaded. Spire with 1 to 5 former varices. Color cream, whitish or bluish gray and with or without 5 or 6 spiral rows of small or large yellowish to reddish brown spots which may coalesce spirally or axially. Last varix of varying thickness, white or with brown or mauve color bars. Inside of outer lip white and with weak or strong, numerous, small teeth. Inside of aperture white, tan or brown. Parietal wall with a weak or fairly strong glaze. Columellar shield with a sinuous, elevated left edge, and bearing rugose, irregular, white lirae. True and false umbilicus deep, open and narrow. Channel posterior to the siphonal canal usually well-developed. Operculum yellowish and smoothish, except for concentric growth lines.

[Indo Pacific Mollusca, Vol 2 No 9. 1968. p12-602]

off Fraser Island

Trawled from 120m depth
47.1 mm

Collected 2014

Tin Can Bay

Trawled from 117m depth
55 mm

Collected 2013

off Gold Coast

On sand and mud
90-100 m depth
Taken by prawn trawlers
61.3 mm

Collected 2003