Ondina divisa

(Adams J., 1797)

Description (shell):
Shell is a moderately tall cone with a blunt apex and intucked protoconch.
When fully grown the shell has four tumid postlarval whorls and the spire is rather narrow. There are shallow spiral grooves on basal half of each whorl (16-20 on the last whorl, 4 on the penult) and opisthocline growth lines. The spiral grooves are separated by low, strap-shaped spiral ridges. Last whorl is large, it occupies about two thirds of shell height. Aperture is elongate, rather narrow; it occupies about40 % of the total height. The base of the aperture flares outwards a little to form a rounded spout. Umbilicus is small. Outer lip has an anal sinus. Tooth is a low bulge.

Up to 4 x 1.8 mm.

White to cream.

Theanimal has a short mentum deeply bifid distally, the two lobes diverging
markedly. The tentacles are short and broad, each with a ciliated lateral groove, the bases joining across the midline where the eyes lie close together. A projection from the mantle skirt at the right extremity of the mantle cavity marks the end of an exhalant ciliary tract. Anteriorly the foot has a pronounced median bay and tentaculiform lateral points; posteriorly it is also partially split in the same way. White, with numerous opaque white points and a reddish patch on the head.

On sandy or gravelly mud from 18 to 200 m deep. Its host is not known.

This species ranges from the Bay of Biscay to the north of Norway (Distr. O. divisa). It has been recorded from around the British Isles except for the southern North Sea, but most records are of dead shells and it is never common.