The longitudinal opening 20 will also allow {TAIL ~ the animal} {HEAD ~ access} to the ball 18 while it is in the track 
The longitudinal opening 20 will also allow { TAIL ~ the animal } { HEAD ~ access } to the ball 18 while it is in the track
OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH