In frog the typical verterbrae are

Options

A. procoelous
B. acoelous
C. amphicoelous
D. amphiplatytan.

Answer

### Step-by-Step Solution:

1. **Understanding Vertebrae Types**: In frogs, there are different types of vertebrae based on their shapes and structures. The main types discussed are procellus, amphicellus, amphiplatiton, and echocellus.

2. **Identifying Procellus Vertebrae**: The procellus vertebrae are characterized by having an anteriorly concave and a posteriorly convex shape. This means that the front part of the vertebra curves inward while the back part bulges outward.

3. **Understanding Other Types**:
- **Amphicellus**: This type has both ends concave, meaning both the front and back parts curve inward.
- **Amphiplatiton**: This type is flat at both ends, meaning there is no curvature at the front or back.
- **Echocellus**: This type is not specifically described in the transcript, but it is another type of vertebra.

4. **Conclusion**: Since the typical vertebrae in frogs are identified as procellus, we conclude that the correct answer to the question is procellus.

5. **Final Answer**: Therefore, the typical vertebrae in frogs are procellus.