In pheretima posthuma pharyngeal nephridia are present in

Answer

To answer the question regarding the presence of pharyngeal nephridia in Pheretima posthuma (the common Indian earthworm), we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Organism**:
- The organism in question is Pheretima posthuma, commonly known as the Indian earthworm.

2. **Understand the Term 'Pharyngeal Nephridia'**:
- Pharyngeal nephridia are excretory structures found in certain annelids, including earthworms. They play a role in filtering waste products.

3. **Locate the Pharyngeal Region**:
- The pharyngeal region of the earthworm is the area where the pharynx is located, which is involved in the ingestion of food.

4. **Identify the Segments**:
- In Pheretima posthuma, the pharyngeal nephridia are specifically located in the 4th, 5th, and 6th segments of the worm's body.

5. **Function of Pharyngeal Nephridia**:
- The primary function of these nephridia is to filter nitrogenous waste from the capillaries. After filtration, the waste is expelled into the pharynx and buccal chamber.

6. **Conclusion**:
- Therefore, the pharyngeal nephridia in Pheretima posthuma are present in the 4th, 5th, and 6th segments.

### Final Answer:
In Pheretima posthuma, pharyngeal nephridia are present in the 4th, 5th, and 6th segments.

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