Plastic stopper for a container, with a measuring cup that serves as a cap

A plastic stopper for a container used for free-flowing media, having a lower portion (1) that can be secured to a container and having a tubular protruding pouring spout (11), a wall (12) surrounding said spout and an intermediate wall (13) therebetween, said wall (12) and intermediate wall (13) forming an annular trough (18) about the pouring spout (11), said trough having a drain (19) for returning the medium to the container, as well as a measuring cup (2) that serves as a cap, said measuring cup having an annular inner wall (23) that fits said pouring spout, said inner wall and said spout being provided with coacting attachment means (17,24) the intermediate wall (13) of said annular trough being raised around its periphery to form an annular shoulder (16) that is inclined towards said spout (11), the lower end of the outer wall (22) of said measuring cup being formed as a sharp edged tapered lip (28), said tapered lip capable of lying on said raised inclined shoulder, when said measuring cup is held on said spout by said attachment means, for forming a sealed closure between said measuring cup and said lower portion.