If you are unsure what part of the shell is being discussed have a look at the 'umbo' on either of these illustrations for more details: http://www.manandmollusc.net/advanced_introduction/bivalve_shell.html http://www.conchsoc.org/aids_to_id/bivalve-parts.php ---------------------------------------------------------------------- [log in to unmask] - a forum for informal discussions on molluscs To leave this list, click on the following web link: http://listserv.uga.edu/cgi-bin/wa?SUBED1=conch-l&A=1 Type your email address and name in the appropriate box and click leave the list. ----------------------------------------------------------------------