{TAIL ~ a first opening} in {HEAD ~ surface portions} thereof adjacent said free extremity and in communication with said passageway, 
{ TAIL ~ a first opening } in { HEAD ~ surface portions } thereof adjacent said free extremity and in communication with said passageway ,
TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH