Cuthona gymnota

(Couthouy, 1838)

This aeolid may reach 22 mm in length; it may be translucent and colourless, or lightly tinted with an orange or rosy hue. The rhinophores are usually rather deeper orange or brown. The cerata are arranged in as many as twelve rows along the sides of the body, with up to seven cerata in each half-row. Each ceras contains a pink-orange or red-brown hepatic lobe. Various quantities of white freckling adorn the ceratal epidermis (C. gymnota-drawing).

Abundant adults, with their egg masses, are often found near the bases of clumps of the hydroid Tubularia indivisa . In more exposed localities around the British Isles, it may be taken on Tubularia larynx , and in American Atlantic localities on Tubularia crocea . It will also prey upon the following hydroids: Bougainvillia ramosa , Sarsia eximia , Garveia nutans and Obelia longissima .

C. gymnota is known from Norway to Arcachon and the Mediterranean Sea (Distr. C. gymnota), as well as the northern USA.