Andrew, There has always been the belief that the larger of a "mated" pair of Cypraea is the female. I do not have access to enough studies where sex was actually determined and related to shell size to answer "yea" or "nay". There are some articles in the Archive site of COWRYS.ORG which address the question. One was in the Hawaiian Shell News and can be seen at http://www.cowrys.org/NSN052CY.HTM#D A second was in Griffiths' THE COWRY and is at http://www.cowrys.org/archive/CWRYV1N4.HTM#P50 Another article about sexual dimorphism in cowries with some mention of size differences is at http://www.cowrys.org/archive/NSN365CY.HTM I recall more but can't put my finger on just who wrote them or when they were printed. I hope that gets you on your way to answering your question. Bob Dayle http://www.cowrys.org _________________________________________________________________ Get your FREE download of MSN Explorer at http://explorer.msn.com