The vessel and the seal cover have respective surfaces that, when engaged, define {TAIL ~ a circumferential interior passage} between {HEAD ~ the vessel} and the seal cover 
The vessel and the seal cover have respective surfaces that , when engaged , define { TAIL ~ a circumferential interior passage } between { HEAD ~ the vessel } and the seal cover
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH