Cranium and vertebral column are cartilaginous in

Options

A. Myxine
B. Rana
C. Ichthyophis
D. Catla

Answer

To solve the question "Cranium and vertebral column are cartilaginous in," we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Question**: We need to identify which group of animals has a cartilaginous cranium and vertebral column.

2. **Identify Key Terms**: The terms "cranium" and "vertebral column" refer to the skull and backbone, respectively. The term "cartilaginous" indicates that these structures are made of cartilage rather than bone.

3. **Recall Animal Groups**: The question suggests looking into different classes of animals. We need to consider groups that are known for having cartilaginous structures.

4. **Consider Cyclostomata**: The class Cyclostomata, which includes jawless fish like hagfish (genus Myxine), is known for having a cartilaginous cranium and vertebral column.

5. **Evaluate the Options**: The options provided are:
- A) Mixin
- B) Rana
- C) Esthiophis
- D) Cartila

- **Mixin**: This refers to hagfish, which belongs to Cyclostomata and has a cartilaginous structure.
- **Rana**: This is a genus of frogs (amphibians), which have a bony skeleton.
- **Esthiophis**: This refers to a type of limbless amphibian, which also has a bony structure.
- **Cartila**: This refers to cartilaginous fish, but it is not a specific group like Cyclostomata.

6. **Select the Correct Answer**: Based on the information, the correct answer is **Mixin**, as it represents the hagfish, which has a cartilaginous cranium and vertebral column.

### Final Answer:
The cranium and vertebral column are cartilaginous in **Mixin**.