Which one of the following structures in Pheretima is correctly matched with its function?

Correct answer: A. Clitellum - Secretes cocoon

  • A. Clitellum - Secretes cocoon
  • B. Gizzard - Absorbs digested food
  • C. Setae - Defence against predators
  • D. Typhlosole - Storage of extra nutrients

Explanation

In a mature earthworm, the 14th and 16th segments are covered by a prominent dark band of glandular tissues called clitellum which secretes cocoon where fertilization and development takes place. In alimentary canal,the muscular gizzard (8th and 9th segments) helps in grinding the soil particles and decaying leaves. The characteristic feature of the intestine between 26th and 35th segments is the presence of an internal median fold of dorsal wall called typhlosole. This increases the effective area of absorption in the intestine. In each body segment, except the first, last and clitellum, there are rows of S shaped setae, embedded in the epidermal pits in the middle of each segment. Setae can be extended or retracted. Their principal role is in locomotion.

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