Archerd Shell Collection> Shell Classes > Gastropoda >Ovula
Many Ovulidae shells are called "false cowries," because of their similarity to the true Cowries. Others, of which Volva is the most extreme, differ in showing remarkably long anterior and posterior canals. A strikingly colorful, patterned mantle is characteristic of all of the Ovulidae, as it is with the true cowrie molluscs. As shown in the pictures of the live animal (below right), the mantle is normally drawn over the entire shell, thus preserving the shell's highly polished appearance. The shells themselves are generally white, rarely patterned, and they lack a sharply back-curved anterior notch. Denticles ("teeth"), when present, are found only on the outer lip; the opposite side of the aperture is smooth and there is no operculum.
Ovulas live in tropical waters, among colonial animals like soft corals, sea fans and sponges. Ordinarily, the white shell is visible only as a portion of the aperture front, with a darker incurrent siphon obscuring the remaining portion. When under attack, the mollusc's colored mantle seems to serve as camouflage, confounding predators. Contrasting, colored spots result from an accumulation of otherwise noxious chemicals that are retained in the mantle skin (see links below to live ovulids). This feature seems to be an evolutionary adaptation generally characteristic of the entire Cypraeoidea superfamily. It is also shared with the more advanced sea slug (nudibranch) families. The Ovulidae, Cypraeidae and Pediculariidae families comprise the Cypraeoidea superfamily.
Volva volva (Linnaeus, 1758)
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Archerd Shell Collection> Shell Classes > Gastropoda > Egg Shells