The pipettes, 40 and 42, are positioned and operated by {HEAD ~ a pipette mechanism} 44 mechanically connected to {TAIL ~ the pipettes} 40 and 42, as indicated by dashed lines 
The pipettes , 40 and 42 , are positioned and operated by { HEAD ~ a pipette mechanism } 44 mechanically connected to { TAIL ~ the pipettes } 40 and 42 , as indicated by dashed lines
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH