Bottle with closure cap

A capped bottle which comprises a bottle having a threaded neck portion of circular horizontal cross-section positioned on a shoulder portion of non-circular horizontal cross-section in head-and-shoulders relationship, a cap threadedly engaging said neck portion, the cap having a tubular socket part which screws onto the neck of the bottle and a skirt part enveloping the tubular socket part and conforming at the hem of the skirt part with the horizontal cross-sectional shape of the shoulder, a notch bearing member on one of the cap and the bottle and a protuberance on the other of the cap and the bottle, said notch bearing member and said protuberance cooperating such that the protuberance bears on said member after the start of the threading movement of the cap onto the neck of the bottle, at least one of the protuberance and notch bearing member deforming to accommodate said threading movement until the protuberance snaps into the notch to terminate said movement, and out of the notch at the start of the threading movement of the cap off the neck of the bottle.