Another set of sinus hairs, the carpal vibrissae, are also likelyto play a role in the positional control of the forelimb. Carpal vib-rissae are well developed in rats (Vincent, 1913). They are locatednear the wrist on the ulnar side of the forearm, and their tips facetowards the substrate in the final stage of the swing phase. The typeand 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 directionalsensitivity than other vibrissae