Page:Natural History, Mollusca.djvu/181

 the change, and one to which so much of the beauty of these shells is indebted. It sometimes happens that the glassy coat envelopes, while soft, any accidentally-intruding body adhering to the shell, and, quickly hardening, detains it there. Specimens of cowries are found in collections, on which other shells are fixed, firmly imbedded in the enamel. As such accidents are rare, however, it may be supposed that the frequent use of the mantle-lobes to embrace the shell has a tendency to prevent the adhesion of other shells.

FULL GROWN COWRY.