The ornamental design for a bathmat for dogs having a removablesponge, as shown and described.
FIG. 1 is a front perspective view of a bath mat for dogs having a removable sponge with the sponge inserted in a cavity in the mat showing my new design;
FIG. 2 is a right side view of a bath mat for dogs having a removable sponge;
FIG. 3 is a left side view of a bath mat for dogs having a removable sponge;
FIG. 4 is a back view of a bath mat for dogs having a removable sponge;
FIG. 5 is a top view of a bath mat for dogs having a removable sponge;
FIG. 6 is a bottom view of a bath mat for dogs having a removable sponge; and,
FIG. 7 is an exploded front perspective view of a bath mat for dogs having a removable sponge showing the manner of assembly with the sponge removed.