{TAIL ~ a first flow sensor} in {HEAD ~ fluid communication} with the first one of the reagent storage reservoirs 
{ TAIL ~ a first flow sensor } in { HEAD ~ fluid communication } with the first one of the reagent storage reservoirs
TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH