The middle-sized melibe, with cerata branched like weed and no radula at all.
A soft, translucent sea slug to about 6 cm, mottled grey-brown to olive, with an expandable fringed oral hood at the front and four to six pairs of cerata along the back. The cerata are the character: their surfaces are covered in fine branched papillae, so the outline of the animal is shaggy and reads as a scrap of weed rather than as a slug. Melibe viridis is far larger, up to 15 cm, with broad smooth-surfaced cerata; Melibe colemani is almost transparent with four flattened wedge-shaped cerata a side and no branching. Between the three, size and the texture of the cerata do most of the work.
The family has lost its radula altogether, which almost no other sea slug has done. The hood is swept open over the sediment or the weed, dropped onto a small crustacean and closed, and the prey is passed whole to the mouth — amphipods, copepods and small shrimp. The animal sheds cerata readily when handled and gives off a strong sweet, fruity smell out of the water, which is a defensive secretion rather than a curiosity.
Recorded from about 3 to 25 m among weed, hydroid turf and rubble. It is cryptic rather than scarce, and a disturbed one will swim off by flexing hard from side to side, which is usually how a hidden animal announces itself.
Ratings are per location: 1 means found on most dives that look for it, 5 means a handful of records. Where enough dives have been logged the figure is calculated from them; otherwise it is an editorial estimate, and says so. We publish habitat and destination, not the dive site.
