Question

Distinguish between the following
A) Prostomium and peristomium
B) Septal nephridia and pharyngeal nephridium

Answer 1

Hint: The kingdom animalia is divided into many groups according to their characteristics, annelids is one of the groups of animal kingdom that includes all the worms found in the earth that consist of segmented bodies.

Complete Answer:
- Annelids are triploblastic organisms that consist of bilateral symmetrical bodies. All the worms belong to phylum annelida, their nervous system, body cavity, body wall, and the kidneys are segmented.
- The prostomium is the head part which is fleshy and segmented and the periosteum is the first segment of the body of annelid.
- The difference between the prostomium and peristomium is that, the prostomium is the front of the mouth found in annelid while peristomium is the surrounding of the mouth opening. The prostomium involves many sensory organs that help annelids to thrust inside the soil.

A)

Sl.No	Prostomium	Peristomium
1.	It is the part of the head that is found in front of the mouth.	It is the front segment that surrounds the mouth of annelids.
2.	Older segments of the body of annelids	Oldest segment of the body of annelids
3.	Composed of sensory organs in the mouth of annelids	Does not contain any organs like prostomium
4.	Prostomium is the true segment of the body.	It is not the true segment of the body.

B) Now, the difference between the septal nephridia and pharyngeal nephridia is that; the septal nephridia found on both the side of intersegmental septa in the fifteenth segment and that open in the intestine while the pharyngeal nephridia is found in three paired tufts in the sixth, fifth, and fourth segments.
Note: The Nephridia found in annelids includes one more type that is mesonephric integumentary Nephridia it is found in the extreme tiny and open in the body wall of the annelids.