Mollusca
Mollusca is a phylum that consists of octopuses, snails, and mussels. It is believed that there are over 100,000 species of mollusca today.
Mollusks generally have an open circulatory system besides squids and octopi. This means that the blood does not circulate within vessels. It is collected then pumped by the heart, and released into the spaces in the tissues from which it returns to the gills and then to the heart. This cycle continues non-stop. A blood-filled space is known as a hemocoel or blood cavity.
Mollusks generally have an open circulatory system besides squids and octopi. This means that the blood does not circulate within vessels. It is collected then pumped by the heart, and released into the spaces in the tissues from which it returns to the gills and then to the heart. This cycle continues non-stop. A blood-filled space is known as a hemocoel or blood cavity.