Name a reptile which has a rudimentary third eye and is treated as primitive and as connecting link?

Options

A. Anguis
B. Naja
C. Sphenodon
D. Ophisaurus

Answer

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks for a reptile that possesses a rudimentary third eye and is regarded as primitive and a connecting link in the evolutionary chain.

2. **Analyzing the Options**: The options provided are:
- Anguis (slow worms)
- Naja (cobras)
- Sphenodon (tuatara)
- Ophisaurus (snake-like lizards)

3. **Identifying Key Features**:
- **Rudimentary Third Eye**: This refers to a small eye structure that is not fully developed but serves some function.
- **Primitive Characteristics**: This indicates that the reptile has retained features that are considered ancient or ancestral.
- **Connecting Link**: This means the reptile exhibits traits of both amphibians and reptiles, showing evolutionary significance.

4. **Evaluating Each Option**:
- **Anguis**: Known as slow worms, these are legless lizards and do not have a third eye.
- **Naja**: This genus includes cobras, which are venomous snakes and do not possess a third eye.
- **Sphenodon**: Known as tuatara, this reptile has a rudimentary third eye located on its forehead, making it a candidate for the answer.
- **Ophisaurus**: This genus consists of snake-like lizards and does not have a third eye.

5. **Conclusion**: Based on the analysis, **Sphenodon** is the only reptile among the options that has a rudimentary third eye, is considered primitive, and serves as a connecting link between amphibians and reptiles.

6. **Final Answer**: The reptile with a rudimentary third eye that is treated as primitive and as a connecting link is **Sphenodon**.