Tinted Cantharus, Transparent Egg Cases
The Tinted Cantharus, Gemophos tinctus (Conrad, 1846), is a resident of oyster beds in the bays and estuarine areas of the tropical western Atlantic in general and Southwest Florida in particular. That marine gastropod doesn’t invite much attention, probably because of its size, about 25 to 28 mm (about one to 1.5 inch) long, or prosaic shape and coloration. Tinted Cantharus are known to feed on the barnacles that thrive on oyster reefs, using their ribbon of teeth, the radula, to reach through the shelly barnacle carapaces. Robert Bachand photographed a living Tinted Cantharus and her egg cases, or capsules, which are shaped like small, fat disks with a depression in the middle. In Bachand’s photo, the transparent egg case walls allow you to see small eggs in the early stages of development. Females of many species of marine gastropods manufacture egg cases that act as barriers against predators and that contain nutritional substances that feed the embryos in the early stages of the mollusks’ lives.