Hey!
There are many animals with no hearts at all, for example; starfish, sea cucumbers and coral , jellyfish don't have a heart . They are all sea animals. Jellyfish is the biggest animal that doens't have a heart, the organisms which have no heart, function through different body parts

There are few animals which don't have heart in there body. Some of this animals are mostly ocean living such as Jelly Fish, Cucumber, Coral & Star Fish.

There are also some animal which have multiple hearts such as:

• Octopuses have three hearts.
• Hagfish have four hearts!
• Earthworms have 5 hearts.

Have a great day!