Sentence:  Along a line nearly corresponding with the horny band which proceeds from the insertions of the shell-muscles and encircles the mantle below, the <WSD>pallial</WSD> 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. 
Meaning of the word marked with <WSD> tags:  Of, pertaining to, or produced by a mantle, especially the mantle of mollusks.