Thanks Tom, Sarah, Peter and Bob,
You've convinced me.  They are juvenile Strombs.  I don't know what I was
thinking when I typed 25cm as the size.  That would be enormous.  Sorry to
mislead you Sarah. Too much easter chocolate I think.  The two small ones are
about 70mm.  Following Peter's criteria,  mine are also are strongly
"corded" at the top of the columella, and a very pale, almost unnoticeable
pink.  The larger one is about 130 mm,  and the columella is a much darker
pink.  In the case of the larger one the lip may have been filed ( I got it
in a box of unlabelled shells a long time ago, and the smaller ones are from
Florida).  The spire is greater than one third of the height of the shell and
has prominent knobs similar, but not quite as long as an adult Strombus
gigas.  The exterior of the body whorl is also "corded", more so in the small
specimens.  So, I think juvenile Strombus gigas they are (not very "gigas"
yet though).  Thanks again, this one had me baffled, but the question that
was asked about the juvenile Tridacna got me thinking on this tangent, so
whoever asked that question, thank you too.
 
Peter Egerton wrote:
 
> Hello,
> No, juvenile Strombus don't have stromboid notches.
> I remeber when I first started collecting shells as a kid, I had
> several shells that I couldn't identify, even as far a family...
> they turned out to be, you guessed it, young strombus! My juvenile
> Strombus gigas is still pink inside with strong cording at the top
> of the columella, Strombus costatus is pure white inside with no cording,
> luhuanus is pink with a dark columella. What you have to do is look
> at the spire only and go through your books comparing that, then you
> will find the right adult match.
> Happy Easter,
> Peter
>
> >Can anyone tell me if juvenile Strombus gigas, (say about 25 cm long)
> >has an obvious strombal notch?  (I am starting to think that this is
> >what my "mystery" shells may be - the ones I thought might be a
> >Hemifusus or a Busycon).  My specimens don't have one.
> >Thanks!
> >
> >Nora Bryan
> >Calgary, Alberta
> >CANADA
> >
> >
> Peter Egerton, Vancouver, Canada
> Collector of worldwide Mollusca