Abstract: In connection means comprising a hook projecting from one structure member and shaped for engagement with an elongated hole having a portion of downwardly tapered shape in another structure member, the hook is complemented by a boss which projects from the same face of the said one member, but spaced from the hook in the vertical direction, and which engages in a said hole in the other member. In a preferred embodiment, the boss is of a shape, for example a truncated pyramid with a trapezium base, engageable by its sides with the sides of the same hole with which the hook is engaged. The hook and boss are integral with the said one member, the boss being disposed closely above the hook from which it is separated by a transverse web. The sides of the boss are undercut. A spring-loaded locking device may be provided in conjunction with the boss.