Is this a sea slug?

February 2, 2005
From: Dominic Rutherford

I saw this washed up on the beach on Benguerra Island, Mozambique in August 2004. I know very little about this kind of marine life, and have no idea what this could be.
Is this a sea slug?

Locality:  Benguerra Island, Mozambique, Mozambique channel, Indian Ocean. Length: 9 inches (approx).14 August 2004. washed up at low tide. Photographer: Dominic Rutherford

Dominic Rutherford

Rutherford, D., 2005 (Feb 2) Is this a sea slug?. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from

Dear Dominic,
Yes this is a sea slug. It is lying upside down in your photo and the large gill, I have labelled in red, identifies it has a pleurobranch slug, commonly called 'side-gilled slugs' because of this large gill which sits hidden under the mantle on the right side of the body. The gland I have labelled is the large pedal gland which these animals have at the posterior tip of the foot. The yellow bit poking out of the mouth are the pair of hard jaws which sit on either side of the mouth.

From its colour I suspect it a dark form of Pleurobranchus forskalii. I have been preparing some Fact Sheets on the pleurobranchs but the are not quite ready as yet

Best wishes,
Bill Rudman

Rudman, W.B., 2005 (Feb 2). Comment on Is this a sea slug? by Dominic Rutherford. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from

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