Reference signs not mentioned in the description and claims may not appear in the drawing, and vice versa.
Reference signs appearing in the drawing must be given in the description and the claims taken as a whole. As regards use of these signs in the claims, reference should be made to F‑IV, 4.19.
Features of a drawing should not be designated by a reference in cases where the feature itself has not been described. This situation may arise as a result of amendments to the description involving the deletion of pages or whole paragraphs. One solution would be to strike out on the drawing reference signs which have been deleted in the description. Such corrections would have to be made in accordance with Rule 49(12).
Where for any reason a figure is deleted then of course the applicant or proprietor ought to delete all reference signs relating solely to that figure appearing in the description and claims.
In the case of applications dealing with complex subjects and incorporating a large number of drawings, a reference key may be attached to the end of the description. This key may take whatever form is appropriate and contain all the reference signs together with the designation of the features which they indicate. This method could have the advantage of standardising the terminology used in the description.