*pallial*

a. [ L. pallium a mantle. See Pall. ] (Zool.) Of or pertaining to a mantle, especially to the mantle of mollusks; produced by the mantle; as, the pallial line, or impression, which marks the attachment of the mantle on the inner surface of a bivalve shell. See Illust. of Bivalve. [ 1913 Webster ]

Pallial chamber (Zool.), the cavity inclosed by the mantle. --
Pallial sinus (Zool.), an inward bending of the pallial line, near the posterior end of certain bivalve shells, to receive the siphon. See Illust. of Bivalve. [ 1913 Webster ]