An ornamentaldesign for an undergarment for an eighteen-inch doll, as shown and described.
FIG. 1 is a front view of an undergarment for an eighteen-inch doll, shown in a position of use;
FIG. 2 is a front perspective view of the undergarment for an eighteen-inch doll of FIG. 1;
FIG. 3 is a front elevational view of FIG. 2 shown in an open position;
FIG. 4 is a rear elevational view of FIG. 2 shown in an open position;
FIG. 5 is a left side elevational view of FIG. 4;
FIG. 6 is a right side elevational view of FIG. 4;
FIG. 7 is a top plan view of FIG. 3; and,
FIG. 8 is a bottom plan view of FIG. 3.
The broken lines, shown as dash-dot-dot-dash lines, depict environmental subject matter of the undergarment for an eighteen-inch doll that forms no part of the claimed design. However, evenly-spaced dashed lines depict stitching of the undergarment for an eighteen-inch doll that forms part of the claimed design.