FIG 8 also shows {HEAD ~ the spherical indented shape} of the two outside walls 216 which are formed by {TAIL ~ a subsequently applied covering} 
FIG 8 also shows { HEAD ~ the spherical indented shape } of the two outside walls 216 which are formed by { TAIL ~ a subsequently applied covering }
OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL