Arthropoda, Mollusca and Echinodermata · Zoology

The 'Pearl' in oysters is formed by the deposition of nacreous layers around a foreign particle. Which part of the mollusc secretes these layers?

  1. The outer edge of the foot
  2. The mantle epithelium
  3. The digestive gland
  4. The gill filaments
Show answer and explanation

Correct answer: The mantle epithelium

When a foreign particle lodges between the shell and the mantle, the mantle epithelial cells respond by secreting concentric layers of nacre (aragonite crystals bound by conchiolin) around the irritant. Over time, these layers accumulate to form a pearl.

Difficulty: Medium Question 17 of 20

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