Janolus hyalinus

(Alder & Hancock, 1854)

The length of this rare species may reach 26 mm, the body cream coloured with red-brown blotches and a few white patches on the central dorsum. The cerata are numerous, finger-like and warty, forming a pair of latero-dorsal series which are continuous around the frontal margin. Within each ceras can be discerned a central diverticulum of the digestive gland extending only half-way up; the most anterior cerata lack such tributaries. The bases of the dark speckled rhinophores are united by the swollen, wrinkled, sensory, caruncle. The anal papilla is postero-dorsal. The head bears short oral tentacles (Janolus hyalinus).

This species has been found on various species of Bugula .

British records are sparse. Elsewhere it has been reported from the SW Netherlands, the Normandy and Brittany coasts of France (Distr. J. hyalinus) and from the Mediterranean Sea (to the Bay of Naples). The most southerly locality was Morocco.