Along {TAIL ~ the body} 8 is {HEAD ~ a plurality} of lateral, crescent shaped grooves 10, 12, disposed on opposite sides of the device in alternating fashion 
Along is
Along { TAIL ~ the body } 8 is { HEAD ~ a plurality } of lateral , crescent shaped grooves 10 , 12 , disposed on opposite sides of the device in alternating fashion
REL TAIL TAIL TAIL TAIL TAIL TAIL OTH REL HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH