by the current created by the cilia that line the groove. As well as crawling around, this feather star can swim short distances by flapping its arms. A. bifida is dioecious, each individual being either male or female. Gametes are produced, mostly between May and July, from the genital canals found at the base of some arms. The eggs stick to the outside of the pinnules where fertilisation takes place. The female produces a mucus net and protects the developing embryos by holding her arms together in what is described as brooding behaviour. After about five days, the eggs hatch into free-swimming larvae which soon settle on a solid surface and attach themselves with a short stalk. Now known as pentacrinoid larvae, they have a similar feeding system to that of the adults. Eventually they develop clawed cirri and become detached from their stalks, reaching maturity in one to two years. Ecology A. bifida has a symbiotic relationship with the marine worm, Myzostoma cirriferum. The worm larvae are caught by the tube feet of the feather star and treated like food particles. They attach in the ambulacral grooves of the pinnules where they undergo metamorphosis and mature. They hold on with parapodial hooks and can move about on the host. References External links Antedonidae Fauna of the Atlantic Ocean Animals described in 1777 Taxa named by Thomas Pennant