Which of the following does not belong to phylum Coelenterata

Options

A. Sea pen
B. Sea father
C. Sea cucumber
D. Sea fan

Answer

To determine which of the following does not belong to the phylum Coelenterata (also known as Cnidaria), we will analyze each option provided.

### Step-by-Step Solution:

1. **Understanding Coelenterata (Cnidaria)**:
- Coelenterata, or Cnidaria, includes organisms that have specialized cells called cnidoblasts. This phylum primarily consists of jellyfish, corals, sea anemones, and hydras.

2. **Analyzing the Options**:
- **Option 1: Sea Pen (Cpen)**:
- The scientific name is *Pennatula* (or *Penatulasia*). Sea pens are indeed part of the phylum Coelenterata. Therefore, this option belongs to Coelenterata.

- **Option 2: Sea Feather**:
- The sea feather is another name for the sea pen, which is also classified as *Pennatula*. Thus, this option also belongs to Coelenterata.

- **Option 3: Sea Cucumber**:
- The scientific name for sea cucumber is *Holothuroidea*. Sea cucumbers are not part of Coelenterata; they belong to the phylum Echinodermata. This option does not belong to Coelenterata.

- **Option 4: Sea Fan**:
- The scientific name for sea fan is *Alcyonaceae*. Sea fans are part of the phylum Cnidaria. Therefore, this option belongs to Coelenterata.

3. **Conclusion**:
- After analyzing all the options, we find that the Sea Cucumber (Option 3) is the only organism that does not belong to the phylum Coelenterata. It belongs to the phylum Echinodermata.

### Final Answer:
The organism that does not belong to the phylum Coelenterata is **Option 3: Sea Cucumber**.

---