The Conchological Society of Great Britain and Ireland

Usual length to 10 mm, width to 6 mm. Flexible, varies between flat [image3] and upturned saucer [2]. Body dorsum nearly smooth, with a few small tubercles [1]. Ground colour [4] of dorsal surface light sandy brown, yellowish, or off-white. Surface usually has small black or sepia flecks [5] that mimic small inhalent pores on compound ascidians such as Trididemnum (EML). Also markings of various colour, including pure white, ochre and yellow which may be arranged to resemble larger exhalent openings of compound ascidians. Yellow marks are often found near the mantle edge [1]. Front edge of mantle curved into a cylindrical siphon with a cut along anterior face, so can be uncurled [7] at times. Underside of mantle and upper surface of foot may be speckled with fine light grey flecks [8]. No gills or tentacles on the dorsal body surface [6]. Smooth tentacles and no snout on head [13]. Underside of foot paler [9] than dorsal body surface. Slit runs across underside of foot near front edge.

 Shell [92]

Longest dimension to about 5 mm, width to about 4 mm. Permanently enclosed in body, fragile, translucent white. Large aperture, so boat or ear shape. Spire barely perceptible, does not protrude beyond outer lip of aperture when shell viewed in plan [92]. Rarely washed up intact. 

Possible ambiguity over shell sizes in published accounts because of difficulty in measuring conventional height (apex to furthest point of aperture) of these fragile and unusually shaped shells, and perhaps confusion in collections of shells of L. perspicua and L.latens. Longest dimension of shell is usually half length of body.