The ornamental design for a combined shower stall and floor toilet, as shown.
FIG. 1 is a perspective view taken from the front and one side of a combined shower stall and floor toilet showing my new design, with a portion of the side broken away for convenience of illustration;
FIG. 2 is a cross sectional view taken on line 2--2 of FIG. 1;
FIG. 3 is a front elevational view thereof; and
FIG. 4 is a fragmentary cross sectional view taken on line 4--4 of FIG. 1.