a second opening in {HEAD ~ surface portions} thereof longitudinally spaced from said first opening and {TAIL ~ toward said free extremity}, 
a second opening in { HEAD ~ surface portions } thereof longitudinally spaced from said first opening and { TAIL ~ toward said free extremity } ,
OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH REL REL REL OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH