<Question, I can't find these specimens in my limited shell
references, are there common names associated with the shells in
question? Thanks,
Michael>
Michael, both shells are slit shells - that's the common name of the
family.  I don't think most of the slit shells are sufficiently
widely known to have generally accepted common names.  Based on
scientific name and place of origin, Pleurotomaria westralis might be
called the western slit shell or the Australian slit shell.  P.
tangaroana might be called the Tangaroa slit shell or the New Zealand
slit shell.  However, these names do not have widespread general
acceptance like map cowrie or bat volute.
Paul M.
Rhode Island