Answers are grounded in this paper and cite their sources.
The inorganic composition of the extrapallial fluids of Mercenaria mercenaria, Mytilus edulis and Crassostrea virginica was significantly different from sea water. Calcium was the principal ion bound in the extrapallial fluids. This binding was accomplished by a non-dialyzable component that appeared to be a glycoprotein.
No takes yet. Share an insight, caveat, or question.
M.A. Crenshaw (1972) studied this question.
Synapse has enriched 10 related papers. Consider them for comparative context: