For lack of a better name, I am calling this nudi "Hoover".
It has a thin flat body with "leafs" sticking out of its back and fluffy eyes that protrude on the end of eyestalks. Hoover can attach itself to objects using its bottom flat edge, but is very comfortable swimming. It has a huge round mouth filled with cilia around the inside lip. As it feeds, the mouth gets about as large as a 50 cent piece, the cilia extend outward like a broom, and it scrapes the surface drawing in food. As the mouth closes, the cilia retract back into the mouth capturing anything it caught.
There are a number of benthic species of Melibe in the tropical Indo-West Pacific. Melibe viridis can grow to over 120mm in length. Their most unique attribute is their method of feeding. They have lost their radular teeth and have developed the oral veil into a large veil or "fish net" which they use to constantly scan the substrate as they crawl along. When the sensitive papillae on the inner edge of the oral veil touch a small crab or crustacean the edge of the veil is rapidly contracted, trapping the prey, which is then ingested. Some species of Melibe, but not this species, harbour zooxanthellae in their bodies. (seaslugforum.net)