We must now remove the animal from its shell. It is well to boil it first, for this does away with the annoying mucous secretion that is freely exuded by glands in the foot when the creature is roughly handled. Alcoholic specimens are apt to be much contracted and hardened, and are therefore less satisfactory as subjects for anatomical study. If it is not convenient to boil the [pg334] specimen, break away the shell with a hammer, using care not to lacerate the soft, fleshy portion within; when this is accomplished, wash the animal carefully to remove the slimy exudation. Note the "visceral hump," which is spiral, and which formerly occupied the upper-whorl portion of the shell. The thin skin covering it is the mantle, which below is greatly thickened and free, lying about the foot like a heavy fleshy flap. MANTLE The mantle-edge in both of these examples is simple; that is to say, it possesses no fringe of tentacles, nor is it supplemented by extra processes, characters which mark many genera of marine /Gasteropoda/. In /Fulgur/ and /Buccinum/ the mantle-edge does not protrude below the edge of the shell; but in many genera, especially those which possess smooth, glossy shells, like the cowries (/Cypræa/) and the graceful /Oliva/, the mantle is proportionately very much larger. In these two genera, when the animal is extended, as in crawling about the sand, the mantle curves upward and incloses a large portion of the shell itself. Indeed, in some genera the shell is almost entirely concealed by this extension of the mantle (/Sigaretus/, /Natica/, etc.). When the shell is removed, the folding of the mantle which constitutes the siphon can be plainly seen. The office of the siphon has already been referred to, also the fact that the presence of a siphon in the gasteropod mollusk may always be determined by merely glancing at the shell alone, for a notch at the base of the aperture indicates the place through which the siphon passed. In /Buccinum/ this is merely a notch, but in /Fulgur/ the siphonal canal of the shell is much longer. Just why the long siphons of some mollusks should be naked and exposed to danger, while others are so carefully protected by elongated, portions of the shell, is a mystery, but nature is full of such contradictions. THE GASTEROPOD FOOT The foot is long, broad, and flat on the under side, like a disk. The variations in the gasteropod foot are almost infinite. [pg335] In some of the species it is amazingly large and powerful, as in /Polynices/ (/Natica/), and in most of the forms which live along sandy beaches. These are sometimes provided in front with a wedge-shaped process called the /propodium/, which serves admirably as a plow to push aside the heavy wet sand through which the animal forces its way. In /Nassa/, which is so common all along our coasts, the foot has two terminal appendages or points behind.