Question 5
Distinguish between the following
(a) Prostomium and peristomium
(b) Septal nephridium and pharyngeal nephridium
(a)
Prostomium | Peristomium |
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. | The first body segment in the earthworm is called the peristomium. It surrounds the mouth opening. |
Septal nephridium | Pharyngeal nephridium |
They are present on both sides of inter-segmental septa behind the 15thsegment and they open into the intestine. | They are present as three paired tufts in the fourth, fifth, and sixth segments. |
