Barnacle Species Stock Video Footage

Barnacles are encrusters, attaching themselves temporarily to a hard substrate. The most common, "acorn barnacles" (Sessilia), are sessile, growing their shells directly onto the substrate. The order Pedunculata (goose barnacles and others) attach themselves by means of a stalk. Free-living barnacles are attached to the substratum by cement glands that form the base of the first pair of antennae in effect, the animal is fixed upside down by means of its forehead. In some barnacles, the cement glands are fixed to a long, muscular stalk, but in most they are part of a flat membrane or calcified plate. A ring of plates surrounds the body, homologous with the carapace of other crustaceans. These consist of the rostrum, two lateral plates, two carinolaterals, and a carina. In sessile barnacles, the apex of the ring of plates is covered by an operculum, which may be recessed into the carapace. The plates are held together by various means, depending on species, in some cases being solidly fused. Inside the carapace, the animal lies on its stomach, with its limbs projecting downwards. Segmentation is usually indistinct, and the body is more or less evenly divided between the head and thorax, with little, if any, abdomen. Adult barnacles have few appendages on their heads, with only a single, vestigial pair of antennae, attached to the cement gland. The eight pairs of thoracic limbs are referred to as "cirre", which are feathery and very long, being used to filter food, suc... Learn more about Barnacle