These plates 34 are preferably formed so as to be integral with one another and so as to be connected along the line 36 of a polymer material such as polypropylene which is recognized to have hinge-like properties when utilized as in thehinge structure 32.The plates 34 are secured to the base 12 and the lid 14 through the use of appropriate conventional fasteners 38 so that the rear ends 18 and 26