shell-gland

Century Dictionary and Cyclopedia

1. n. The shell-secreting organ of a mollusk. It appears at a very early period of embryonic development, and is the active secretory substance of the shell-sac or shell-follicle. The original shell-gland of the embryo may be transient and be replaced by a secondary shell-forming area, or may be permanently retained in a modified form.
2. n. An excretory organ of the lower crustaceans, as entomostracans, forming a looped canal in a mantle-like fold of the integument, one end being cæcal, the other opening beneath the mantle: so called from its position beneath the shell. See cuts under Apus and Daphnia.
3. n. In flatworms, the gland which supplies the material for the formation of egg-shells.