I must say this thread has been a learning experience for me.  I admit
to being a bit of a "Latin snob", and was initially going to snap off a
snooty reply entitled "Common names- who needs them??"  I get confused
when people use anything but the scientific name, because there seems to
be little agreement re the "proper" common name for many species- in my
neck of the woods, for example, *all* Buccinidae are referred to as
either "conchs", or "whelks", depending on which part of the province
one is asking in.  Nucella lapillus L. is sometimes a "dog whelk",
sometimes a variety of winkle, and on the "French shore", something else
again (dessert, perhaps?).  So, i have studiously avoided using them, in
order to save the strain on the brain.  When children ask the name of
the shells i give them, often as not i make something up ( and none of
them has ever come back to tell me i was "wrong" yet!!), or just
Anglicise the scientific name (which should not be called the "Latin"
name anymore, since it is just as likely to be Japaneese, Greek, or the
name of somebody's wife or pet cat!)- Strombus canarium L. becomes the
canary conch (which is indeed sometimes a beautiful canary yellow, by
the way, and which i have never heard called anything to do with dogs,
until today!), Cyp. maculosa becomes the maculated cowrie, and Distorsio
anus i just don't get involved with!!  Of course, such obvious critters
as "angel wings", "little deer cowries", and moon snails are easy, but
then there are "frog shells", wentletraps, and "Tun shells" which make
no sense at all in modern-day English....  But, i wander, as usual.  I
now agree with those who have pointed out that common-language names do
indeed have  a valid and useful role in introducing people to the wild
and wonderful world of shells, and they can be rather fun as well.
However, to rely on them for the purpose of exact identification is at
best hazardous.
        A footnote:  Contrary to Mr. Nister's comments, a common name can never
be "wrong" or erroneous in any real sense: they are simply the name
given to an organism or group of organisms related more often by shape
and/or function than by phylogenetic affinity, by any given community:
There can be no "right" or "wrong" in this context, since the purpose of
the designation is everyday communication, which has no correlation with
scientific accuracy.
 
        Thank-you also to those who made some very learned observations on the
nature of memory.
                                                                                                                        -Ross M.
 
P.S.:  I am reminded by all this of a cautionary tale told by someone
whose name (Latin or otherwise!) escapes me.  He was describing an
uncomfortable situation he had run into at a party:  " I once
encountered a bore of a particulaly obnoxios kind.  He knew the names of
10,000 shells, with which he insisted upon torturing me, despite the
particular that i showed no interest whatsoever in his obsession." (or
words to that effect!)