Which of the following statements is incorrect?

Options

A. Mucosal epithelium has goblet cells which secrete mucus for lubrication.
B. Mucosa forms gastric glands in the stomach and crypts in between the bases of villi in intestine.
C. Cells lining the villi has brush border or microvilli.
D. All the four basic layers in the wall of gut never show modifications in different parts of the alimentary canal.

Explanation

To determine which statement is incorrect regarding the histology of the alimentary canal, we will analyze each option step by step.

### Step-by-Step Solution:

1. **Option 1: Mucosal epithelium has goblet cells which secrete mucus for lubrication.**
- **Analysis:** This statement is correct. The mucosal epithelium indeed contains goblet cells that secrete mucus, which serves to lubricate the intestinal contents and protect the epithelial lining.

2. **Option 2: Mucosa forms gastric glands in the stomach and crypts in between the bases of the villi in the intestine.**
- **Analysis:** This statement is also correct. The mucosa does form gastric glands in the stomach, which secrete gastric juices, and it contains crypts (crypts of Lieberkühn) in the intestine that secrete intestinal juices.

3. **Option 3: Cells lining the villi have brush border or microvilli.**
- **Analysis:** This statement is correct as well. The epithelial cells lining the villi of the intestine have microvilli, which increase the surface area for absorption.

4. **Option 4: All the four basic layers in the wall of the gut never show modification in the different parts of the alimentary canal.**
- **Analysis:** This statement is incorrect. The four basic layers of the gut wall (serosa, muscularis externa, submucosa, and mucosa) do show modifications in different parts of the alimentary canal. For example, the muscularis externa in the stomach has an additional oblique layer, which is not present in other parts of the alimentary canal.

### Conclusion:
The incorrect statement is **Option 4**: "All the four basic layers in the wall of the gut never show modification in the different parts of the alimentary canal."