Hemolymph
Hemolymph (or
haemolymph) is the
blood analogue used by those
animals, such as all
arthropods and most
mollusks, that have an open
circulatory system. In these animals there is no distinction between blood and interstitial fluid. The liquid fills all of the interior (hemocoel) of the body and surrounds all
cellss.
Hemolymph is composed of water, inorganic salts (mostly Na, Cl, K, Mg, and Ca), and organic compounds (mostly carbohydrates, proteins, and lipids).
There are free-floating cells, the hemocytes, within the hemolymph. They play a role in the arthropod immune system.