Cardiovascular System of the clam worm
Clam worms are aquatic, and have been observed in shallowed marine habitats. Much like other worms in annelid phylum, the clam worm has a closed circulatory system. They also contain a dorsal and ventral blood vessel. Very similarly to its earthworm brethren, the dorsal and ventral blood vessels are connected by five pairs of aortic arches. The aortic arches act as pumps, to bring blood from the dorsal blood vessel to the ventral blood vessel.