Tritonia lineata

Alder & Hancock, 1848

This delicate species may measure up to 34 mm in length; the body is white, sometimes with a pinkish blush, limaciform and slender. A conspicuous longitudinal opaque white line runs from the head back along each side of the dorsum. The white line communicates with the base of each gill and is united mid-anteriorly and mid-posteriorly with its partner of the other side. Up to six pairs of pallial gills may be present, erect and arborescent. The oral veil is produced to form two pairs of elongated finger-like papillae.

There is uncertainty about the diet of T. lineata . It has been assumed that it fed upon Alcyonium digitatum (perhaps largely because it so closely resembled this prey), but aqualung divers have only rarely found T. lineata on or near Alcyonium . The more likely prey is the inconspicuous octocoral Sarcodictyon catenata , but this suggestion awaits confirmation.

This tritoniid is common in clean, shallow sublittoral localities at scattered localities in the North Sea (Distr. T. lineata). Elsewhere, it is known from the European Atlantic coast from south Norway to Brittany and the Mediterranean Sea (Naples).