Morphology and function of the antennular joint and its strand organ,instrumental to gravity reactions in the spiny lobster Panulirus argus (Crustacea,Decapoda)

Summary The one-point joint linking the antennula with the carapace in Panulirus argus is described. A strand organ is activated when the antennula is moved in the vertical plane. Its structure, function, and regeneration after severance were investigated.The implications of this system are discussed, starting from the findings that the strand organ counteracts the statocyst (located in the antennula) in such a way that gravity reactions occur only if the body changes its position with respect to gravity.The work was supported by grants from the Max-Planck-Gesellschaft (Hedwig Schöne), the National Science Foundation of the U.S.A., the American Philosophical Society, and the Cecil Montgomery-Moore Fellowship of the Bermuda Biological Station. Contribution No. 836 of the Bermuda Biological Station