Onchidoris depressa

(Alder & Hancock, 1842)

This uncommon but distinctive species is characterized by its small size (up to 9 mm in length) and very flattened profile. The mantle is so translucent that the eyes and the glistening calcareous spicules can be discerned with a lens. The mantle is pale brown, with a pattern of bright orange spots tending, towards the midline, to possess a central black spot. A conspicuous and constant feature is the presence on the mantle of evenly spaced, uniformly long, soft tubercles. Up to twelve simple pinnate gills are present around the anal papilla. The head bears an oral veil without tentaculate processes.

This dorid has been recorded from intertidal localities and shallow offshore waters. Feeding has been reported on the bryozoan Schizomavella linearis .

It is known to occur on the Atlantic coast of France, and at Banyuls-surMer in the Mediterranean Sea. In the North Sea restricted to the British coast (Distr. O. depressa).