Around the notch 43 is a plurality of {HEAD ~ pivotally disposed main ribs} 45 for supporting {TAIL ~ the cover} 41 
for supporting
Around the notch 43 is a plurality of { HEAD ~ pivotally disposed main ribs } 45 for supporting { TAIL ~ the cover } 41
OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH