EVERYDAY SCIENCE

Detailed explanation-1: -In earthworms and leeches, the clitellum is a swollen glandular portion of the body that is not segmented as the rest of the body. It is helpful in secreting a viscid sac into which eggs are stored.

Detailed explanation-2: -Leeches and oligochaetes comprise a monophyletic group of annelids, the Clitellata, whose reproduction is characterized by simultaneous hermaphroditism. While most clitellate species reproduce by cross-fertilization, self-fertilization has been described within the speciose genus Helobdella.

Detailed explanation-3: -The clitellum is a thick, saddle-like ring found in the epidermis (skin) of the worm, usually with a light-colored pigment. To form a cocoon for its eggs, the clitellum secretes a viscous fluid. This organ is used in sexual reproduction of some annelids, such as leeches.

Detailed explanation-4: -The Clitellata are a class of annelid worms, characterized by having a clitellum-the ‘collar’ that forms a reproductive cocoon during part of their life cycles. The clitellates comprise around 8, 000 species. Unlike the class of Polychaeta, they do not have parapodia and their heads are less developed.