Which one of the following is not correctly matched ?

Options

A. Flame cells-platyhelminthes
B. Stinging cells-coelenterates
C. Metameric segmentation-molluscs
D. Gill slits-chordates

Explanation

To determine which option is not correctly matched, we will analyze each option one by one:

1. **Flame Cells - Platyhelminthes**:
- Flame cells are specialized excretory cells found in flatworms, which belong to the phylum Platyhelminthes.
- This option is correctly matched.

2. **Stinging Cells - Cnidarians**:
- Stinging cells, also known as cnidocytes, are characteristic of the phylum Cnidaria, which includes organisms like jellyfish and corals.
- This option is also correctly matched.

3. **Metameric Segmentation - Mollusca**:
- Metameric segmentation refers to the division of the body into repeated segments. This feature is primarily observed in the phylum Annelida (e.g., earthworms) and not in Mollusca (e.g., snails, clams).
- This option is not correctly matched.

4. **Gill Slits - Chordates**:
- Gill slits are a feature found in all members of the phylum Chordata, including fish and amphibians, during some stage of their development.
- This option is correctly matched.

After analyzing all options, we conclude that the incorrect match is:

**Metameric Segmentation - Mollusca**.