"Dentalium: B, the shell of Dentalium Entalis, broken longitudinally, showing the animal in a contracted state. C, the shell, showing the animal advancing out; a and b, the foot, the lobes of which are developed in the form of a corolla; c, a part of the collar of the mantle. E, the animal, magnified, extricated from the shell, with them antle slit along the dorsal and medial line, detached in part from its posterior insertion, and turned aside so as to show the parts enclosed; a, the extremity of the foot, which closes the aperture j, of the collar lm, of the mantle nop; bb, lobes of the fot; c, the foot itself, presenting a depression or a channel, running its whole length; d, the head; e, the cerebral ganglion; f, f, the two sides of the mouth; g, g, the membranes which support the branchiae; gg, ii, the branchiae; pp, qq, the retractor muscles; s, the muscle of insertion; t, the expanded posterior extremity, in which is situated the vent." — Chambers' Encyclopedia, 1875

Dentalium

"Dentalium: B, the shell of Dentalium Entalis, broken longitudinally, showing the animal in a contracted…