The oval body is 10-30 mm long and up to 10 mm wide. The translucent or whitish animal is tinged with orange-red or reddish-brown along the intestinal trunk and its lateral branches, and dotted with white. The intestinal trunk has 3-6 lateral branches; anterior end of the intestinal trunk trifurcates into one median branch and two lateral branches passing by the cerebral organ to reach the marginal tentacles. Each of the marginal tentacles is covered with 60-70 eyes. There are also numerous eyes between the marginal tentacles. Each elongate cerebral group contains about 200 eyes, the two groups converging anteriorly (E. cornuta-diagrammatic).
The male pore is situated midway between the mouth and the ventral sucker, ventrally to pharynx; the male copulatory complex consists of muscular seminal vesicle, an independent prostatic organ and a penis-papilla with a stylet in the penis-pocket. The female pore is situated close to the posterior end of the pharynx; the vagina is short and simple; shell-chamber widened, dorso-ventrally compressed; no [t]Lang's vesicle[/t]; the uterine canals are confluent posteriorly, each with a lateral vesicle.
On muddy sand, mud and shells, Laminaria and corallines in low-tidal waters and especially among red algae in depths to 20 m.
Recorded from Norway and Sweden. Further records from Pas-de-Calais, Berwickshire, Belfast Bay, Firth of Forth, Guernsey, Channel Islands, Plymouth and the western Mediterranean.