Histochemical Studies on the Clam Mactra solidissima.

Abstract

Heparin-like substances in the clam do not arise from mast cells such as exist in higher vertebrates. Four different acid mucopoly-saccharides in the clam are descr. A heparin-like anticoagulant (Mactin A) extracted from the clam is probably a mixture of all 4 types, but appears to consist mostly of the mucopolysaccharides of the ground substance of the connective tissues. Ribonucleic acid is present in association with acid mucopolysaccharide in the mucous glands on the shell side of the mantle. Ca, phosphate and alkaline phosphatase are present in different sites in the epithelium and subjacent tissues of both sides of the mantle and are not topographically related to the mucous glands.