Octopuses have 3 hearts, which is partly a consequence of having blue blood. Their 2 peripheral hearts pump blood through the gills, where it picks up oxygen. A central heart then circulates the oxygenated blood to the rest of the body to provide energy for organs and muscles.
Earthworm possess 5 pairs heart. Earthworms do not have a genuine heart because they are worms, but they do have aortic arches, which connect ventral and dorsal veins and pump blood.
Cockroach has a 13 chambered tubular heart. Oxygenated blood enters each chamber through a pair of a slit like openings called ostia. The first chamber opens into aorta which further opens into head sinuses.
Squids also have three hearts. They are part of the cephalopod family alongside octopuses, cuttlefish and nautiluses. All cephalopods have three hearts and blue blood.
Snails usually have two heart chambers, one atrium and one ventricle. Few groups have two atriums, making the heart a three-chambered one. There is a valve between atrium and ventricle to prevent the blood from flowing back.
The cuttlefish's pair of orange gills filter oxygen from seawater and deliver it to the bloodstream. The cuttlefish has three hearts, with two pumping blood to its large gills and one circulating the oxygenated blood to the rest of its body.
The hagfish circulatory system also includes multiple accessory pumps throughout the body, which are considered auxiliary "hearts". Hagfish are the only known vertebrates with osmoregulation isosmotic to their external environment.