A metering pump or segment, and a metering pump assembly comprising a plurality of the metering pumps or segments, are disclosed. The drive shaft assembly for driving the pump gears of each metering pump or segment is coaxially aligned with the longitudinal axis of the pump or segment, as is the fluid inlet. The single drive shaft assembly is utilized to drive all of the metering pumps or segments comprising the metering pump assembly, and the different metering pumps or segments are fluidically connected together by means of a common fluid passageway. In addition, the different metering pumps or segments can be interchanged or exchanged so as to permit different metered fluid output volumes to be outputted at different predetermined locations, and the dispensing volumes can also be added together.