Re: Hancockia californica feeding

February 5, 2008
From: Bernard Picton

Concerning message #12295:

Hi Bill,

Just looking to see what you had on Hancockia as Steve Trewhella just found some on a box which had been cast up on the shore in Dorset, south coast of England, together with Goose barnacles and hydroids. I've only found Hancockia uncinata on a few occasions, but it seems to feed on the hydroid Clytia hemisphaerica. I don't know the Californian hydroid fauna, but the one that Hancockia californica is feeding on has very similar morphology to Clytia hemisphaerica and I would guess that it is also a species of Clytia.

Bernard Picton

Picton, B. E., 2008 (Feb 5) Re: Hancockia californica feeding. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from

Dear Bernard,

Someone sent me an email recently asking why I still had a message of theirs on the Forum from 5 years ago and could I remove it because it was out of date. Your reference to Sean Kearney's 4 year old message is a good example showing why nothing on the Forum is  'out of date'. Facts and photos certainly don't become invalid through age and having a record of opinions and identifications changing over time as more information becomes available is very instructive in reminding us that we are not infallible.

Hopefully someone in California may be familar enough with the local hydroids to confirm your suggested identification. As you will have seen H. uncinata has not made the Forum yet so if you or Steve Trewhella has any photos of his recent find they would be welcome.

Best wishes,
Bill Rudman

Rudman, W.B., 2008 (Feb 5). Comment on Re: Hancockia californica feeding by Bernard Picton. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from

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