Which of the following structure is connected with double ventral nerve cord in periplaneta americana ?

Options

A. Supra - pharyngeal ganglion
B. Sub-oesophageal ganglion
C. Sub-pharyngeal ganglion
D. supra-oesophageal ganglion

Answer

To solve the question regarding which structure is connected with the double ventral nerve cord in Periplaneta americana (the American cockroach), we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Nervous System of Periplaneta americana**:
- The American cockroach has a nervous system that includes a double ventral nerve cord, which is a characteristic feature of many arthropods.

2. **Identify the Structures Mentioned in the Options**:
- The options provided are:
- a) Suprafarangial Ganglion
- b) Subesopharyngeal Ganglion
- c) Subpharyngeal Ganglion
- d) Supraesophageal Ganglion

3. **Evaluate Each Option**:
- **Suprafarangial Ganglion**: This is located above the pharynx and is not directly connected to the double ventral nerve cord. Therefore, this option is incorrect.
- **Subesopharyngeal Ganglion**: This ganglion is located below the esophagus and is indeed connected to the double ventral nerve cord. This is the correct answer.
- **Subpharyngeal Ganglion**: This term is often used interchangeably with the subesopharyngeal ganglion, but in this context, it is not the correct term for the structure connected to the double ventral nerve cord.
- **Supraesophageal Ganglion**: This ganglion is located above the esophagus and is part of the central nervous system, but it does not connect directly to the double ventral nerve cord. Thus, this option is also incorrect.

4. **Conclusion**:
- Based on the evaluation, the structure that is connected with the double ventral nerve cord in Periplaneta americana is the **Subesopharyngeal Ganglion**.

### Final Answer:
- **b) Subesopharyngeal Ganglion**