Q.The clitellum is a distinct part in the body of earthworm Lampito mauritii, it is found in?

The earthworm (Pheretima posthuma) has a long, cylindrical, segmented (metameric) body without a distinct head, bearing a reproductive clitellum, genital pores, and chaetae used for burrowing and movement.

Morphological features of the earthworm:

1. Shape and segmentation: The body is long, cylindrical and bilaterally symmetrical, divided into about 100–120 ring-like segments (metameres) — metameric segmentation.
2. No distinct head: There is no clearly differentiated head; the mouth lies in the first segment (peristomium) and is overhung by a small fleshy lobe, the prostomium, used to sense food and help in burrowing.
3. Clitellum: Segments 14, 15 and 16 are swollen, glandular and darker, forming a collar-like clitellum ('saddle') that secretes mucus for cocoon formation during reproduction.
4. Genital openings:
   • A single male genital pore lies mid-ventrally on segment 18.
   • A single female genital pore lies mid-ventrally on segment 14.
   • Four pairs of spermathecal apertures lie on the ventro-lateral sides in the grooves between segments 5/6, 6/7, 7/8 and 8/9.
5. Dorsal pores: Minute pores in the mid-dorsal line from about the 12th segment onward release coelomic fluid that keeps the body surface moist.
6. Chaetae (setae): Each segment except the first and last bears a ring of minute S-shaped chitinous chaetae embedded in the body wall, used to grip the burrow during locomotion.
7. Body wall and colour: A thin, moist cuticle covers the epidermis; the body is brownish dorsally and paler ventrally.

[!ANSWER]

The earthworm has a long, cylindrical, metamerically segmented body with no true head (only a prostomium), a glandular clitellum on segments 14–16, a male pore on segment 18, a female pore on segment 14, four pairs of spermathecal pores in grooves 5/6–8/9, dorsal pores for coelomic fluid, and chaetae on each segment for locomotion.