How does blood circulate in most mollusks?

Answer 1

* Oxygenated hemolymph (blood), coming from ctenidia, flows into heart's atria, * then it flows into heart's ventricle, which pumps the hemolymph into arteries, * from arteries, hemolymph flows into the hemocoel; * then it's caught again inside veins and brought directly into afferent ctenidial vessels or into accessory branchial hearts, which pump it inside ctenidia again, for oxygenation. Hemolymph flows also into the pericardium, the celomatic membrane wich contains the systemic heart, and, from it, hemolymph reaches and flows into the excretory ducts.

Answer 2

In most mollusks, blood circulates through an open circulatory system. The heart pumps blood into a cavity called the hemocoel, where it comes into direct contact with the organs. The blood then flows back to the heart through sinuses and vessels.