FIG. 1 is a perspective view of a watch casing showing my new design;

FIG. 2 is a right side elevational thereof;

FIG. 3 is a left elevational view thereof;

FIG. 4 is a first end elevational view thereof;

FIG. 5 is a second end elevational view thereof;

FIG. 6 is a top plan view thereof; and,

FIG. 7 is a bottom plan view thereof.

The dotted lines are intended to show features that are environmental only and form no part of the claimed design.