The Total solution for NCERT class 6-12
a) Prostomium andperistomium
Prostomium
Peristomium
Small, fleshy lobe, serves as a covering for the mouth and as a wedge to force open cracks in the soil wherein the earthworm crawls.
It is the crescentic aperture at the anterior end of the first segment of the earthworm comprising the mouth
b) Septal nephridiumand pharyngeal nephridium
Septal nephridium
Pharyngeal nephridium
Found at the anterior and posterior surface of septa occurring after segment 15 in earthworm
Found in three pairs in the 4th, 5th and 6th segments located on either side of the alimentary canal
Excretory matter is discharged into the lumen of the alimentary canal
Excretory matter is discharged into the gut, in the pharynx or buccal cavity