The underside of each channel base provides a relatively large lateral dimension for fastening individual channels together by {HEAD ~ means} of a transverse stringer or {TAIL ~ strut} 
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The underside of each channel base provides a relatively large lateral dimension for fastening individual channels together by { HEAD ~ means } of a transverse stringer or { TAIL ~ strut }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL