Another set of sinus hairs, the carpal vibrissae, are also like lyto play a role in the positional control of the forelimb. Carpal vibrissae are well developed in rats (Vincent, 1913). They are located near the wrist on the ulnar side of the forearm, and their tips face towards the substrate in the final stage of the swing phase. The type and distribution of mechanoreceptors in the follicle-sinus com-plex of these hairs differ from those of other sinus hairs (Fundinet al., 1995), indicating that carpal vibrissae have less directional sensitivity than other vibrissae. Fundin et al