Abstract: A demountable panel system has panel members formed with peripheral edge surround sections of extruded rigid material. The surround sections included channels to receive panel material and leg portions with opposed grooves to releasably engage with a clip rail section. The clip rail section enables various panel structures, such as corner posts, to be interconnected with the panel members. The clip rail section has a tongue extending generally in the direction perpendicular to the panel member and so shaped as to be resiliently engageable with a tongue of an adjacent clip rail section whereby panel members or other panel structures can be clipped together along their length by relative transverse movement. The clip rail section includes opposed, outwardly extending flanges and perpendicular leg parts which cooperate with the channels of the surround section to form a recess having a narrow mouth.