Re: Hermaea sp. from Hachijo Island Japan

May 9, 2002
From: Kathe R. Jensen

Dear Shouichi and Bill,
This animal certainly does look like Hermaea bifida. I checked Baba's paper on "stiligerids", but none of them seem to fit this animal. The other possibility is the East Pacific H. oliviae, which I have never seen alive, but judging from the picture in Dave Behrens' book (as Aplysiopsis oliviae) it is more darkly coloured. Or the West Atlantic H. cruciata, which I think has fewer lateral branches on the digestive gland tubules in the cerata.

The next question then is: How did it get there? Probably on algae in ballast water - or on "fouling" algae. This is an increasing problem, which especially for "rare" species, may completely obscure natural distributions.


Jensen, K.R., 2002 (May 9) Re: Hermaea sp. from Hachijo Island Japan. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from

Thanks Kathe,
Bill Rudman


Hermaea cf. bifida

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