The structure includes {HEAD ~ a body} for extending around the container opening and a membrane for occluding {TAIL ~ the container opening} 
The structure includes { HEAD ~ a body } for extending around the container opening and a membrane for occluding { TAIL ~ the container opening }
OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL