Notochord occurs only in the larva of

Options

A. Balanoglossus
B. Amphixus
C. Herdmania
D. Cephalodiscus

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks about the occurrence of notochord specifically in the larva of certain organisms. We need to identify which organism from the given options has a notochord only in its larval stage.

2. **Analyzing the Options**:
- **Balanoglossus**: This organism is a member of the subphylum Cephalochordata. In Cephalochordates, the notochord is present in both larval and adult stages.
- **Amphioxus**: Similar to Balanoglossus, Amphioxus is also a Cephalochordate, which means it possesses a notochord in both its larval and adult forms.
- **Herdmania**: This organism belongs to the subphylum Urochordata. Urochordates exhibit a phenomenon known as retrogressive metamorphosis, where the larval form has a notochord that is lost in the adult form.
- **Cephalodiscus**: Like Balanoglossus and Amphioxus, Cephalodiscus is also a Cephalochordate, retaining the notochord in both life stages.

3. **Identifying the Correct Answer**: Based on the analysis, Herdmania is the only organism in the options provided that has a notochord only in its larval stage and not in the adult stage. Therefore, the correct answer is **Herdmania**.

4. **Conclusion**: The notochord occurs only in the larva of Herdmania, which is a urochordate.

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