Dicyemida, also known as dicyemids, are a group of small, parasitic invertebrates that live in the kidneys of certain species of cephalopod mollusks, such as octopuses and cuttlefish. They are characterized by their complex body structure, which consists of a series of interconnected tubes that run through the host's renal tubules. Dicyemids feed on the host's renal secretions and are believed to play a role in maintaining the health of the host's kidneys. Much remains to be learned about the biology and evolution of this group of animals. Despite their small size and parasitic lifestyle, dicyemids are of interest to scientists because of their unique anatomy and their close association with cephalopod mollusks, which are considered to be among the most intelligent of all invertebrates.