The ornamental design for a decanter and base, as shown and described.
FIG. 1 is a front view of the decanter and base showing my new design.
FIG. 2 is a back view of the decanter and base.
FIG. 3 is a front view of the decanter and base in use condition.
FIG. 4 is a perspective right side view of the decanter and base.
FIG. 5 is a perspective left side view of the decanter and base.
FIG. 6 is a left side view of the decanter and base.
FIG. 7 is a right side view of the decanter and base; and,
FIG. 8 is a top view of the decanter and base.
The broken lines in the drawing views represent unclaimed portions of a decanter and base, which are included for the purpose of illustrating unclaimed environment only, and forms no part of the claimed design.