Acteocina fusiformis (A. Adams, 1850)

Description

A small cylindrical-fusiform cephalaspidean reaching just a few millimetres in shell length. The shell is white, smooth and semi-translucent, with very faint longitudinal sulci; the spire is elevated and acuminate, with about five whorls slightly channelled above the suture. The aperture is linear, contracted at the middle and dilated anteriorly. The columella bears a single callous plication, and the outer lip is inflected medially.

Distribution

Type locality: the China Sea (Cuming collection). The species is recorded from the western Pacific.

Etymology

The specific epithet fusiformis is Latin for "spindle-shaped" (from fusus, a spindle), in reference to the elongate fusiform contour of the shell, expressed by Adams as "testa cylindrico-fusiformi".

Remarks

Originally described as Bulla fusiformis by A. Adams in the "Monograph of the Family Bullidae" of Sowerby's Thesaurus Conchyliorum. The diagnosis explicitly compared the species to Tornatella bullata Kiener.

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References

• Bulla fusiformis, Adams A. (1850-1854). Monograph of the Family Bullidae. In: Sowerby G.B. II (ed.) Thesaurus Conchyliorum, or Monographs of Genera of Shells. Vol. II (Part XVI-XVII): 553-608, pls. 119-125. Sowerby, London.
• ツムガタコメツブガイ Acteocina (Tornatina) fusiformis (A. Adams, 1850), 奥谷喬司. (2000). 日本近海産貝類図鑑. 東海大学出版会.