Prostomium | Peristomium |
1.Prostomium is a lobe, which covers the mouth at the anterior end. | 1.Peristomium is the first body segment. |
2.Prostomium has a wedge to force open cracks in the soil.3.It is sensory in function. | 2.The mouth is present in the peristomium.3.It is commonly called as buccal segment. |
Septal nephridium | Pharyngeal nephridium |
These are present on either side of the inter-segmental septa from segments 15th to the last. They open into the intestine. | These are present as paired tufts.They are present in the 4th ,5th , and 6th segement. |