(Kowalewsky & Marion, 1887)
Description:
Elongate, vermiform animals. The body is mainly circular in section but the sides may be slightly convex. The body lacks a dorsal keel; the distinct ventral groove is united with the fold; and the cloaca lacks secondary respiratory structures. The body surface appears fairly smooth, the thick cuticle being pierced by stalked, club-shaped papillae arising from the hypodermis and bearing several layers of hollow, needle-like calcareous spicules; hooked spicules and cloacal spines are absent. The radula is degenerate but salivary glands are well-developed.
Size:
Up to 35 x 3 mm.
Colour:
Yellowish-grey.
Habitat:
In depths of 50 m or more and they are usually associated with the hydroid Lytocarpia (Theocarpus) myriophyllum around which they are found coiled and twisted.
Distribution:
This is a southern form found widely in the Mediterranean; rare in the North Sea (Distr. R. aglaopheniae).