Dear friends Conus marmoreus definitely has an operculum. However, it is not rare to observe individuals of this or any other species lacking an operculum. Alternatively, from time to time I have observed individuals having two operculi! I believe that the operculum may suffer from damage during the live of the animal, and eventually falls off, being replaced by a new one. This process takes time. For this reason, it is not unusual to see large individuals having what seems to be a very thin and small operculum, and smaller individuals having a larger, thicker one. At least, this is my experience with the collecting of many individuals of varied species of cones, mainly in the Cape Verde Islands. The observations that I mention were mostly made on species of the venulatus group, but I have also observed Chelyconus ermineus individuals having no operculum, so this is quite common I think. However, I must mention that there are species which indeed lack an operculum, specially in certain genera of Conilithidae or Conorbiidae. Warmest regards Manuel Jimenez Tenorio Jerez, Cadiz, SPAIN ---------------------------------------------------------------------- [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. ----------------------------------------------------------------------