cooperating means on each of said display cases for retaining adjacent display cases releasably in {HEAD ~ vertically stacked relation} for {TAIL ~ pivotal movement} of their front and rear compartments as units about a common vertical axis, and 
for
cooperating means on each of said display cases for retaining adjacent display cases releasably in { HEAD ~ vertically stacked relation } for { TAIL ~ pivotal movement } of their front and rear compartments as units about a common vertical axis , and
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH