Abstract: A support member for connecting panels of a curtain wall to horizontal mullions. Each mullion has a channel formed therein and has shoulders at opposite sides of the channel. The panel support member comprises a rigid bar, positioned in the channel in the mullion, and a tenon extending longitudinally of the bar. Anchor lugs extend outwardly from opposite sides of the tenon. A gasket, having panel receiving slots formed therein, has a groove extending longitudinally thereof to receive the tenon and anchor lugs. As anchor bolts are tightened, drawing the bar into the channel in the mullion, external abutments on the gasket are drawn into the channel such that a portion of the gasket is captured between the shoulders and the lugs to resist deformation of the gasket relative to the load carrying tenon.