The Closed circulatory circuit is a type of blood circulation in which the blood flows through the channels called as the blood vessels (Arteries and the veins).
The blood is always moved in the blood vessels in the closed circulation. When heart pumps the blood, it goes to smaller vessels, which carries them to different organs. It is the better way of transportation of the blood then the open circulatory circuit.
Following are the examples of the animals with closed circulatory system: octopus, earthworms, squids, all vertebrates, example humans, wild animals etc.