Barnacle 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
What Is and What Should Never Be (Supernatural) What Is and What Should Never Be (Supernatural) "What Is and What Should Never Be" is the twentieth episode of the paranormal drama television series "Supernatural"s second season. It was first broadcast on May 3, 2007 on The CW. The narrative follows series protagonist Dean Winchester (Jensen Ackles) who finds himself in an alternate reality after a confrontation with a djinn . The creature appears to have fulfilled Dean's greatest wish: that his mother had not been killed when he was a child. Dean is happy in the new world until it becomes apparent that his previous work as a