an elongated hopper door extending across {HEAD ~ the full width} of the box along {TAIL ~ the bottom} of the hopper to form a part of the bottom thereof 
an elongated hopper door extending across { HEAD ~ the full width } of the box along { TAIL ~ the bottom } of the hopper to form a part of the bottom thereof
OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH