Solution

Prostomium :
Prostomium is a small fleshy lobe, which overhangs the mouth of an earthworm. It helps the organism push into the soil and is sensory in function.
Peristomium :
The first body segment in the earthworm is called the peristomium. It surrounds the mouth opening.
Septal nephridium :
They are present on both sides of intersegmental septa behind the 15th segment and they open into the intestine.
Pharyngeal nephridium :
They are present as three paired tufts in the fourth, fifth, and sixth segments.