Select the mismatch among the following.

Options

A. Chondrichthyes -Placoid scales
B. Columba – Diaphragm
C. Balanoglossus - Proboscis glands
D. Limulus- Chitinous cuticle

Answer

To solve the question of selecting the mismatch among the given options, we will analyze each option step by step.

### Step 1: Analyze Chondrichthyes
- **Definition**: Chondrichthyes are a class of cartilaginous fish that include sharks and rays.
- **Characteristic**: They have a skeleton made of cartilage, and they possess placoid scales.
- **Conclusion**: This is a correct match.

### Step 2: Analyze Columba and Diaphragm
- **Definition**: Columba refers to a genus that includes pigeons and doves.
- **Characteristic**: The diaphragm is a muscular structure found in mammals that aids in respiration.
- **Conclusion**: Since Columba (pigeons) are not mammals, they do not have a diaphragm. This is an incorrect match.

### Step 3: Analyze Balanoglossus and Proboscis Gland
- **Definition**: Balanoglossus is a genus of hemichordates.
- **Characteristic**: Hemichordates possess a proboscis gland, which serves as an excretory organ.
- **Conclusion**: This is a correct match.

### Step 4: Analyze Lingula and Chitinous Cuticle
- **Definition**: Lingula is a genus of brachiopods, which are marine animals.
- **Characteristic**: They have a chitinous cuticle, which is a characteristic of many invertebrates.
- **Conclusion**: This is also a correct match.

### Final Conclusion
After analyzing all the options, the mismatch is between **Columba** and **Diaphragm**. Therefore, the correct answer to the question is the second option.