Pallial

the pallial line, or impression, which marks the attachment of the mantle on the inner surface of a bivalve shell

The oldest points are close to the outcrop of the pallial myostracum (9 ).

Along a line nearly corresponding with the horny band which proceeds from the insertions of the shell-muscles and encircles the mantle below, the pallial wall is produced inwards and forwards into a membranous fold or ligament, which I will call the pallio-visceral ligament; and this pallio-visceral ligament becoming attached to various viscera, divides the great fifth chamber into an anterior inferior, and a posterior superior portion, which communicate freely with one another.