The ornamental design for a cover for a toiletseat or similar article, as shown and described.
FIG. 1 is a perspective view of a cover for a toilet seat according to the invention.
FIG. 2 is a front, elevation view of the cover.
FIG. 3 is a rear, elevation view of the cover.
FIG. 4 is a right side, elevation view of the cover.
FIG. 5 is a left side, elevation view of the cover.
FIG. 6 is a top, plan view of the cover; and,
FIG. 7 is a bottom, plan view of the cover.
The broken lines in FIGS. 1, 2, 4, 5 and 6 showing other structure of the cover are illustrative of environmental structure only and do not form a part of the claimed design.