Elysia viridis

(Montagu, 1804)

The leaf-shaped body may reach 45 mm in length and the lateral parapodial 'wings' may be outstretched or held over the dorsum so that they nearly meet in the midline. The body colour varies with the diet, from green to red. Relatively constant features are, however, tiny glistening red, blue, and green specks. White patches may also be found, especially at the edges of the parapodia, and black markings are sometimes seen on the head and elsewhere. Ramifying diverticula of the digestive gland and of the albumen gland are often visible through the skin of the parapodia and even of the rhinophores and other parts of the head. The anal opening is antero-lateral. The rhinophores are prominent and inrolied. The characteristic parapodial lobes make their appearance at a body-length of 3 mm; younger individuals may lack them (E. viridis-drawing).

This common species occurs on a variety of shallow-water algae, especially Codium and Cladophora . Despite the graceful form of the body and the wide and mobile parapodial lobes, swimming has never been observed.

It has been recorded from Norway to the Mediterranean Sea (Distr. E. viridis), and there is a doubtful record from Chinese waters.