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