further arcuate portions continuously formed with said respective planar portions and matched to a portion of {HEAD ~ the other arcuate portion} of {TAIL ~ said elongated mating member}, and 
of
further arcuate portions continuously formed with said respective planar portions and matched to a portion of { HEAD ~ the other arcuate portion } of { TAIL ~ said elongated mating member } , and
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH