said corrugations being {HEAD ~ the only protuberances} of said pipe between {TAIL ~ said joints}, 
said corrugations being { HEAD ~ the only protuberances } of said pipe between { TAIL ~ said joints } ,
OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH