The ornamental design for a bathmat, as shown and described.
FIG. 1 is a perspective view of a bath mat showing my new design;
FIG. 2 is another perspective view thereof;
FIG. 3 is a front elevational view thereof
FIG. 4 is a rear elevational view thereof;
FIG. 5 is a left side elevational view thereof;
FIG. 6 is a right side elevational view thereof;
FIG. 7 is a top plan view thereof; and
FIG. 8 is a bottom plan view thereof;
FIG. 9 is an enlarged view of portion 9 shown in FIG. 1;
FIG. 10 is an enlarged view of portion 10 shown in FIG. 2; and,
FIG. 11 is an enlarged view of portion 11 shown in FIG. 2.
The broken lines in the drawings depict portions of the bath mat that form no part of the claimed design. The dot dash lines surrounding the portions that are to be enlarged form no part of the claimed design.