Velum is found in

Options

A. Herdmania
B. Amphioxus
C. Branchiostoma
D. Both B and C

Answer

### Step-by-Step Solution:

1. **Understanding the term "Velum":**
- Velum is an anatomical structure that serves as an organ of locomotion in certain organisms. It is typically located at the front end of the body.

2. **Identifying the organisms in the question:**
- The question lists the following organisms: Hydmania, Amphioxus, and Brachiostoma.

3. **Analyzing the presence of Velum:**
- Velum is specifically noted to be a feature of cephalocordates.
- Both Amphioxus and Brachiostoma are classified as cephalocordates.

4. **Determining the presence of Velum in each organism:**
- **Hydmania:** This organism does not possess a velum.
- **Amphioxus:** This organism possesses a velum.
- **Brachiostoma:** This organism also possesses a velum.

5. **Conclusion:**
- Since Velum is found in both Amphioxus and Brachiostoma, the correct answer to the question is that Velum is found in both B (Amphioxus) and C (Brachiostoma).

### Final Answer:
- The correct option is **both B and C** (Amphioxus and Brachiostoma).