This particular variety of clam (Tridacna species), with its brilliant blue mantle, is a common sight on shallow Philippine reefs. It measures about six inches from end to end. In this photo the fleshy mantle is entirely exposed, but patience is required to see the clam in this state-- the clam will abruptly close its shell with only a minor change in light, such as a shadow. Specialized cells called ocelli along the outer edge of the mantle are responsible for light reception.
To cite this page:
Myers, P., R. Espinosa, C. S. Parr, T. Jones, G. S. Hammond, and T. A. Dewey. 2014. The Animal Diversity Web (online). Accessed at http://animaldiversity.org.
The Animal Diversity Web is an educational resource written largely by and for college students. ADW doesn't cover all species in the world, nor does it include all the latest scientific information about organisms we describe. Though we edit our accounts for accuracy, we cannot guarantee all information in those accounts. While ADW staff and contributors provide references to books and websites that we believe are reputable, we cannot necessarily endorse the contents of references beyond our control.