Melanochlamys cylindrica from New Zealand

May 13, 2003
From: Bill Rudman

To accompany the question on Philinopsis taronga from New Zealand, I have prepared a page on Melanochlamys cylindrica, which is the most common aglajid in New Zealand, often occurring quite abundantly in algal turf on rock platforms. Although its shape and uniform black colour don't excite much interest, its spectacular feeding behaviour certainly does. It feeds on polychaete worms, which it captures and rapidly swallows whole, by sucking them in like a piee of spaghetti. It does this with a greatly enlarged and muscular buccal bulb, which through rapid expansion of the lumen creates a suction, rapidly drawing the worms through the buccal bulb into a large oesophageal crop where digestion takes place. Often when collecting Melanochlamys cylindrica you will find them stuck head down into the algal turf, almost impossible to extract. When you finally loosen them you will often find that they have part of a worm in their mouth. What happens is that when feeding they suck in part of a worm, but the other end is anchored firmly in a crevice or algal holdfast. In these cases, the slug doesn't let go but stays with its mouth losed until it digests the part of the worm it has inside. This an take 5 or 6 hours. At times when feeding animals in aquaria, 2 slugs would suck in the same worm simultaneously - from opposite ends. Physical laws being what they are, this would cause the slugs to hit heads as they sucked in their respective ends of the worm. neither would give way so they would sit head to head for several hours until digestion freed them from each other.
Best wishes,
Bill Rudman

Rudman, W.B., 2003 (May 13) Melanochlamys cylindrica from New Zealand. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from

Related messages

  1. Melanochlamys cylindrica from Whangaparaoa, New Zealand
    From: Graham Bould, July 27, 2009
  2. Shell of Melanochlamys cylindrica
    From: Bill Rudman, December 23, 2004
  3. Melanochlamys cylindrica from New Zealand
    From: Paul Furneaux, June 12, 2003

Show factsheet and all related messages