Maralo,
 
Harry Lee did a 24-species photo feature in the American Conchologist in
the December 1998 issue (p. 18-19) and a program on the same topic last
summer at the Orlando convention. Perhaps Harry will give you a more
complete rundown. Comparing his two photos, and his notes on them, I find
that the shell he  shows as N.antillarum and the shell he shows as N. albus
differ as follows:
 
Ranges appear to overlap considerably:
N. albus: NC-Brasil, Bermuda, all West Indies
N. antillarum: SE FL, Bermuda, all West Indies, Yucatan (?) to Brasil.
 
Protoconchs: (he illustrates these for the two species)
N. albus:  polyspiral protoconch
N. antillarum: conical crawl-away protoconch
Both are classed in the 7-15mm size range.
 
He says there is confusion among four species, inclding these two and also
N. consensus (Ravenel, 1861) from S. Carolina to Yucatan except S tip of
FL, another shell, and a fourth species, N. albus authors, not (Say, 1822)
from S.E. FL to Brasil, Bermuda, all West Indies. All are pictured here
 
The above is from his notes. From my observation of his photos, the axial
ribbing in N. antillarum is more oblique than that in N. albus, and the
spiral  cords on the body whorl are much stronger over the axial ribs in N.
antillarum. The body whorl of N. antillarum is more globose below its
sloping shoulder than N. albus, which appears to have a squarer, knobbier
shoulder, and widen not at all below the shoulder. N. antillarum widens a
bit below the shoulder.
 
The inner (parietal) lip of N. antillarum appears to have many fine
sharpish teeth the length of the lip, while that of N. albus has only a
few--a large rounded one posteriorly and and a few smooth rounded ones
anteriorly. The spire angle of N. albus appears to be more acute than N.
antillarum There may be other differences not discernable in the photos,
and also you may have one of the other two species in question. I suggest
you get a copy of Harry's article and have a look for yourself.
 
Lynn Scheu
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Louisville, KY
 
> In their inventory of shells from the Netherlands Antilles deJong and
>Coomans report N. antillarum (468, Pl. 4,5) and, if I understand their
>presentation, appear to treat their shell as the N. albus  Abbott relegates
>antillarum to synonymity for albus.      Has anyone collected antillarum
>I've collected what I thought was albus in the Keys.  --
>Marlo
>Merritt Island, Florida
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