Question

Select the incorrect statement of pheretima
a. The body segments are metameres about 100-120 in number
b. The dorsal surface is of the body is marked by the presence of genital pores
c. Prostomium is an anterior lobe which covers the mouth
d. The first segment of the body is called buccal segment

Answer 1

Hint: Pheretima is one of the genera of the earthworms and they are generally found in southeast Asia. They got the name because they belong to the genus Pheretima, and these worms have clitellum around the segments of 14 to 16. These worms have a general structure like earthworms except at some changes in the position of reproductive structures.

Complete answer:
- The body of the Pheretima is generally divided into segments called metamers and they are in the range of 100 to 120 in number.
- The first segment of the body is called a buccal segment
- In these worms, the mouth is covered by a structure called Prostomium.
- Pheretima has a glandular tissue that presents around the segments of 14 to 16 is called the clitellum.
- These worms are hermaphroditic, so they can reproduce either sexually or Parthenogenetic.
- In these worms, the female genital pores are present and they are situated ventrally on segment 18.
- Genital papilla may also present on the ventral side.
- In these genus the development of the genus is without the larval stage where they usually develop in cocoons.
- They are nocturnal and they have aversion to light, so they come out only at night, so they feed and reproduce only at night.
- Like all the earthworms, they keep the body moist because they exchange gases through skin.
- They are called farmers' friends as they help in making the soil porous and they generally use vermicomposting.

Hence, the correct answer is option (B).

Note: Pheretima is one of the genus of earthworm, and the main difference between the pheretima with other earthworms are, in pheretima genital pores are present on dorsal surface, while in other species of earthworm genital pores are present on ventral surface of the body.