first retaining means comprising {HEAD ~ a plurality} of {TAIL ~ radially extending means} on said retaining ring, 
first retaining means comprising { HEAD ~ a plurality } of { TAIL ~ radially extending means } on said retaining ring ,
OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH