{HEAD ~ A smoothly arched notch} extends axially to the topmost edge of {TAIL ~ the box end} 
{ HEAD ~ A smoothly arched notch } extends axially to the topmost edge of { TAIL ~ the box end }
HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL