• Norwegian: armføttinger


The lamp shells are sessile (stationary) animals with an appearance similar to bivalves, but they are not closely related. Lamp shells have two valves too, but the valves are differently arranged, on top and below the body, rather than to the left and right. Most lamp shells have two convex valves. They are usually attached to the substrate by a stalk or foot, rather than byssus threads. The shell shape of the class Terebratulida resembles a oil lamp, hence the name. One third of the cavity between the valves is occupied by the body. In the rest of the cavity there are tentackles or lophophores, that filter food from the water. A mantle surrounds the cavity. Oxygen is absorbed through the lophopores and the mantle.


The lamp shells constitute a small phylum, Brachiopoda, including only 300 living species.