Cameos were at one time quite in the fashion, both as ornaments for the person in the way of brooches, and as bric-a-brac about the room. These shell-cameos are made from the genus Cassis, the helmet shells. These are well adapted for this purpose, as the shell is made up of several differently colored layers, making a bas relief figure not only possible but very effective. The black helmet (Cassis madagascariensis) is one of the best for this purpose, the figure being carved from the white, outer layer of shell, which stands out very clearly against the black background of the second layer. When a cameo is desired simply as a brooch or for any other form of personal adornment, a piece of the shell is cut out and shaped into the required form and size—oval, square or other shape—and cemented to a block of wood. The figure is then traced on the shell with a pencil and finally carefully worked out with sharp, pointed steel instruments, of delicate size and form. The same process is resorted to in working out a bas relief on the entire shell, only the latter is placed in a vice or other object to hold it firmly. The home of this industry is Genoa and Rome, Italy, although some are produced in France; these latter, however, are of a poorer quality. Several thousand people are employed in this trade. Many beautiful examples of this work were exhibited at the World’s Columbian Exposition, in Chicago, in 1893. The cameo shells are among the largest of sea snails, several of them measuring eight or ten inches in length and weighing several pounds. They are found only in tropical and subtropical seas, living in comparatively shallow waters on a sandy bottom. They are voracious eaters, living principally on bivalve mollusks. One of the most abundant of mollusks is the violet sea snail (Ianthina communis), which spends its life floating in the waters of the Atlantic Ocean. The shell is very delicate, resembling in form some of the land snails, and has but two colors, both shades of violet, a deep color on the under side (which, by the way, is always turned upward when the animal is floating in the water), and a lighter shade on the upper side. So fragile is the shell that it seems as if a breath would break it. The most interesting fact in connection with this mollusk is the wonderful float or “raft” which is secreted by the foot, and to the under side of which the eggs are attached. The latter are not all in the same condition. Nearest to the animal they are more or less fresh; those in the middle of the float contain embryos and fully formed young, while those on the outer end are empty, the young having escaped into the water. The genus is gregarious and may be found in almost countless numbers. After a severe storm they are sometimes cast upon the beaches in vast numbers, where they soon die under the fierce rays of the sun.