It's quite easy. On powisii there is are clearly visible cords on the whorls of the whole shell. Furthermore the side of the whorls are round. On laurenti the upper whorls are flat in structure and flat on the sides. Joop ---------------------------------------------------------------------- [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. ----------------------------------------------------------------------