the slot elements and {HEAD ~ the guide walls} being provided on {TAIL ~ said port member} as flange structure thereon, 
provided on
the slot elements and { HEAD ~ the guide walls } being provided on { TAIL ~ said port member } as flange structure thereon ,
OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH