{HEAD ~ The two groovelike indentations} 17 on {TAIL ~ both sides} of the insertion slit 9 are in alignment with one another and with the insertion slit 
{ HEAD ~ The two groovelike indentations } 17 on { TAIL ~ both sides } of the insertion slit 9 are in alignment with one another and with the insertion slit
HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH