Distinguish between the followings (a) Prostomium and peristomium
Explanation The body of earthworm is divided into a different segment. These segments are called metameres. Peristomium: Peristomium is the first metamere of earthworm, which surrounds a crescentic aperture at the anterior end known as the mouth. It shows longitudinal wrinkles on its surface. Peristomium is the oldest segment of the earthworm’s body that does not contain any organ. Prostomium: A small, fleshy lob projecting forward above the mouth from the dorsal edge of the peristomium is known as prostomium. It is not a true segment. The prostomium is very sensitive, that lacks sensory appendages and used as a muscular probe in burrowing. Final answer The peristomium is the first segment of earthworms that have longitudinal segments. A mouth surrounds it at the anterior end. The prostomium is a fleshy lobe that is used as a muscular probe for burrowing. It does not contain any sensory appendages.
