(57) This invention provides a container and closure assembly in which the closure is made of suitable plastics material shaped to provide a top to cover the mouth of the container and a depending skirt to embrace the neck of the container. The closure is also provided with an internal cellular ceiling area to match the shape of the rim around the mouth of the container so that when the closure is in its operative position on the container the cellular area acts like a sponge and conforms to any irregularities on the rim to provide a more effective seal.