Pinnules occur over the arms of

Options

A. Asterias
B. Antedon
C. Astropecten
D. Holothuria.

Answer

To solve the question "Pinnules occur over the arms of?", we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Term "Pinnules":**
- Pinnules are defined as soft, feathery branches or spines that are found on certain organisms.

2. **Identify the Options Given:**
- The options provided are:
- A) Astreias
- B) Antedon
- C) Astropectin
- D) Holothria

3. **Analyze Each Option:**
- **Astreias:** Known for having hard spines on their body, not pinnules.
- **Antedon:** This organism has soft, feathery pinnules along its arms.
- **Astropectin:** Similar to Astreias, it has hard spines and does not possess pinnules.
- **Holothria:** Also characterized by hard spines, lacking pinnules.

4. **Conclusion:**
- After analyzing all the options, the only organism that has pinnules (soft, feathery branches) over its arms is **Antedon**.

5. **Final Answer:**
- Therefore, the correct answer is **B) Antedon**.