The rearward section includes an interior chamber and an opening or {HEAD ~ channel} that extends from the chamber to provide a water flow path between the chamber and the surrounding body of {TAIL ~ water} 
The rearward section includes an interior chamber and an opening or { HEAD ~ channel } that extends from the chamber to provide a water flow path between the chamber and the surrounding body of { TAIL ~ water }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL