I do not know if Arbacia lixula hosts any Eulimidae, but try the same host
species in different localities.
It concerns a different species and host, but in the Mediterranean
Coralliophila meyendorffii parasitize sea anemones.  But sometimes you
encounter hundreds of anemones and no Coralliophila, while other times you
hit the right spot.
And this is a general rule with a lot of parasitizing mollusks: Melanella
(Eulimidae) and holoturians, Coralliophila meyendorffii with madreporarians
(yes, it paratizes them too), ecc. ecc.
You can look at a hundred gorgonians and do not find a single Neosimnia
spelta (a mediterranean Ovulidae) and then see your dive buddy looking at
101th and find it, yes unfortunately it happened...
A lot of patience is needed....!
Paolo


At 12.51 03/11/01 +0100, you wrote:
>I tried the systems that you told me with Arbacilla lixula but I didn't
>get anything interesting. I will try it with Diadema antillarum in the
>future.
>Thank you very much


Paolo Giulio ALBANO
Bologna, ITALY
E-mail: [log in to unmask]