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