Thanks to all who answered.  I did find the eulimas on a big black sea cucumber and there is a slight bend in the axis at the tip.  Looks like jamaicensis is most likely.  I note the genus is now Balcis rather than Melanella.
Guido, I'd love to send a picture but neither my SLR (with close-up ring) nor my digital let me get down below about an 8 cm x 8 cm field and these things are under a centimeter, need better stuff, sorry.
>
> From: "M. J. Faber" <[log in to unmask]>
> Date: 2005/06/08 Wed AM 03:15:52 EDT
> To: [log in to unmask]
> Subject: Re: Melanella
>
>
> Probably you either have Balcis jamaicensis (C. B. Adams, 1845), which is known from the big black sea cucumber Ludwigothuria mexicana as well as from the variable coloured Isostichopus badionotus (both shallow water species), or, slightly less likely, B. hypsela (Verrill & Bush, 1900) which is known from the above two holothurians and from Holothuria princeps, another common shallow water species.
> Balcis jamaicensis has often been identified as "B. intermedia Cantraine", which, actually, is a synonym of the European species, Polygireulima sinuosa (Scacchi, 1836). It has been suggested that B. eburnea (Megerle von Mühlfeld, 1824) is an older name for B. jamaicensis.
> Balcis jamaicensis, and B. hypsela have very similar shells, but in the former, the protoconch and early teleoconch whorls are slightly askew, whereas in B. hypsela the axis is straight, not twisted, throughout. Colin Redfern's "Bahamian seashells" (2001) has excellent pictures of both species.
>
> Marien
> www.mollus.nl
>
>
>
> ----- Original Message -----
> From: "John Cramer" <[log in to unmask]>
> To: <[log in to unmask]>
> Sent: Tuesday, June 07, 2005 5:39 PM
> Subject: Melanella
>
>
> > I've just returned from snorkeling in the Bahamas (Andros) and I got several melanellas off a sea cucumber.  They look like conoidea or jamaicensis or hypsela.  The largest is about 8 or 9 mm.  My best guess from pictures is hypsela.  Beautiful shells under low magnification.  I have no information on these species as to distribution, preferred hosts, etc.  Does anyone have an idea which species is most likely or are they all possible?
> >
> > ----------------------------------------------------------------------
> > [log in to unmask] - a forum for informal discussions on molluscs
> > To leave this list, click on the following web link:
> > http://listserv.uga.edu/cgi-bin/wa?SUBED1=conch-l&A=1
> > Type your email address and name in the appropriate box and
> > click leave the list.
> > ----------------------------------------------------------------------
>

----------------------------------------------------------------------
[log in to unmask] - a forum for informal discussions on molluscs
To leave this list, click on the following web link:
http://listserv.uga.edu/cgi-bin/wa?SUBED1=conch-l&A=1
Type your email address and name in the appropriate box and
click leave the list.
----------------------------------------------------------------------