Egg spiralling

March 16, 2004
From: Gilles Matheron

Dear Sir.
For professional reasons (I'm working in show business!) I had to search informations about opisthobranchs, and more specifically Chromodoris annae ...
You mention, about egg coiling, that "Most opisthobranch egg masses seem to spiral in an anticlockwise direction [dextral] - that is coiling in a anticlockwise direction from the centre." [message: #9839]
May I suggest an error in your sentence... as "dextral" rather means "to the right". For instance the Italian language still use these words, with "destra" being "right side" and "sinistra" meaning "left side", respectively "clockwise" and "anti-clockwise".

I know, as you stated, Nudibranchs can be tricky sometimes, and they surely are.
Anyway, your site is a proof passions can be transmitted to non-specialist candid people, like myself. From now on I will keep myself aware of the Nudibranchs day-to-day life !
Sincerely yours.

Gilles Matheron,
Montpellier, France.

Matheron, G., 2004 (Mar 16) Egg spiralling. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from

Dear Gilles,
Thanks for taking the time to let me know of this error. You are of course right. I must have prepared that answer late at night. To save confusion I have corrected my earlier message.

Although nothing to do with slugs, it is interesting to note that there has been a long-held belief in European culture that left-handedness is bad. In medieval times left-handed people were often given a bad time because they were thought to be touched by the devil and until a generation ago teachers were still attempting to force children to become right-handed. The English word 'sinister' meaning evil or untrustworthy is from the same Latin word.

Concerning Chromodoris annae, I am not sure if you found what you were looking for, but if it was about their eggs, they lay, like most chromodorids with black longitudinal lines, a flattened egg spiral, which spirals clockwise from the centre [dextrally].
Best wishes
Bill Rudman

Rudman, W.B., 2004 (Mar 16). Comment on Egg spiralling by Gilles Matheron. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from

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