Umbrella Shell

Found singly or in pairs burrowing under rocks, over mud and sand bottoms of coral and rocky reefs. Shells are often covered in algae and hence the colour varies. The frilly egg mass they lay also varies in colour.

All opisthobranchs are hermaphrodites.
Umbraculidae is a false limpet.
The body is circular, with large pustules. Even when crawling the animal does not elongate and the position of the head can only be determined by the tubular rhinophoral tentacles which extend out from beneath the shell. Below these tentacles the body is split by a "mid-anterior cleft" in which the permanently protruded penis sits and the mouth opens. The radula is very broad with many small rasping teeth. Umbraculum umbraculum is a sponge feeder, and has been recorded on a number of different species of the Demospongia