Title: Barnacle
Content: Barnacle A barnacle is a type of arthropod constituting the infraclass Cirripedia in the subphylum Crustacea, and is hence related to crabs and lobsters. Barnacles are exclusively marine, and tend to live in shallow and tidal waters, typically in erosive settings. They are sessile (nonmotile) suspension feeders, and have two nektonic (active swimming) larval stages. Around 1,220 barnacle species are currently known. The name "Cirripedia" is Latin, meaning "curl-footed". The study of barnacles is called cirripedology. Barnacles are encrusters, attaching themselves permanently to a hard substrate. The most common, "acorn barnacles" (Sessilia), are sessile, growing their shells directly onto the

Title: Whale barnacle
Content: Whale barnacle The whale barnacles are the acorn barnacles that belong to the family Coronulidae. They typically attach to baleen whales, though they may settle on toothed whales and, rarely, turtles. The barnacles passively filter food, using tentacle-like cirri, through the water pushed over themselves by its host during movement, which, being commensals, is done at no cost nor benefit to the host. However, some whales may use the barnacles as protective armor or for inflicting more damage while fighting, making the relationship mutualistic where both parties benefit; though, some species may just increase the drag the host experiences, making

Title: Barnacle
Content: pairs of thoracic limbs are referred to as "cirri", which are feathery and very long, being used to filter food, such as plankton, from the water and move it towards the mouth. Barnacles have no true heart, although a sinus close to the esophagus performs a similar function, with blood being pumped through it by a series of muscles. The blood vascular system is minimal. Similarly, they have no gills, absorbing oxygen from the water through their limbs and the inner membrane of their carapaces. The excretory organs of barnacles are maxillary glands. The main sense of barnacles appears to

Title: Barnacle
Content: used to be considered hermaphroditic, but it turned out that its males inject themselves into the female's body, degrading to the condition of nothing more than sperm-producing cells. Most barnacles are suspension feeders; they dwell continually in their shells, which are usually constructed of six plates, and reach into the water column with modified legs. These feathery appendages beat rhythmically to draw plankton and detritus into the shell for consumption. Other members of the class have quite a different mode of life. For example, members of the superorder Rhizocephala, including the genus "Sacculina", are parasitic and live within crabs. Although

Title: Barnacle
Content: The anatomy of parasitic barnacles is generally simpler than that of their free-living relatives. They have no carapace or limbs, having only unsegmented sac-like bodies. Such barnacles feed by extending thread-like rhizomes of living cells into their hosts' bodies from their points of attachment. Barnacles were originally classified by Linnaeus and Cuvier as Mollusca, but in 1830 John Vaughan Thompson published observations showing the metamorphosis of the nauplius and cypris larvae into adult barnacles, and noted how these larvae were similar to those of crustaceans. In 1834 Hermann Burmeister published further information, reinterpreting these findings. The effect was to move

Question: What kind of creature is a barnacle?
Answer: A crustacean