Dear Kevin;-
        I was going to reply; but you did such a good job, I aint a gonna. Only
one comment: of all discussed species, only E. lamellosum has a basil ridge.
            Art

Kevin Czaja wrote:

> Hi Rita,
>      I understand how the Wentletraps get confusing.  One thing I can tell
> you straight away is the Epitonium lamellosum is not found at Sanibel.  In
> my experience, the 5 most common Sanibel wentletraps are:
> Epitonium angulatum,
> E. humphreysii,
> E. tollini,
> E. rupicola,
> E. multistriatum matthewsae
> (roughly in that order- the first two are much more common than the last
> three).  There are others but they are much rarer.  Of these five, it is
> the first 3 that provide the greatest confusion (especially when the shells
> have become at all worn).  If you find the shell is cream colored between
> the white ribs (costae) it is more likely to be humphreysii.  Humphreysii
> is also typically thicker ribbed than angulatum or tollini.  Though
> humphreysii can have a slight angle to the ribs at each shoulder in a
> pristine shell, angulatum's "angles" tend to be more pronounced (basically
> squared rather than rounded).  Also an adult angulatum tends to be larger
> than humphreysii (3/4-1 inch vs. 1/2 to 3/4 inch).  Although I have found
> plenty of Juvenile angulatum and humphreysii to potentially confuse the
> issue further, it is good to note that juv. angulatum tend to have very
> extreme squared off shoulders.  Tollini, often confused with humphreysii,
> is usually more slender, has strictly rounded costae, and doesn't get above
> a 1/2 inch. Rupicola is unmistakable unless eroded to the point of losing
> all color.  Typically the shell has clear brownish bands that set it
> apart.  Multistriatum matthewsae is usually very small (<1/2 inch) and has
> many ribs per whorl (>15).  This sets it apart from all the preceding
> wentletraps.  I hope this information is helpful.  -Take care, Kevin