Unidirectional Movement Fibres from a Proprioceptive Organ of the Crab, <i>Carcinus Maenas</i>

Abstract

ABSTRACT Proprioception in the legs of arthropods arises in receptor ceils more closely associated with structures of the joints than with muscles. Sensitive endings are located in special internally placed organs (Barth, 1934; Burke, 1954; Alexandrowicz &amp; Whitear, 1957). Studies of the action potentials in the leg nerve during mechanical manipulation of the leg joints in Limulus (Pringle, 1956) and in certain arachnids (Pringle, 1955) have shown the presence of several types of proprioceptive endings. Slow-adapting tonic position fibres, some responding at the flexed and others at the extended positions, were shown to have their endings situated so as to react to strains in the cuticle. The rapidly adapting phasic fibres, however, originate in some internal structures, different fibres responding to the two directions of movement.