Intra-abdominal testes are found in

Options

A. Panthera and Equus
B. Macaca and Macropus
C. Balaenoptera and Delphinus
D. Canis and Felis .

Answer

To determine which organisms have intra-abdominal testes, we need to analyze the provided options based on the characteristics of their reproductive anatomy.

### Step-by-Step Solution:

1. **Understanding Intra-abdominal Testes**:
- Intra-abdominal testes are those that remain within the abdominal cavity. This is a characteristic feature of certain aquatic mammals, as they do not require the cooler external environment for spermatogenesis.

2. **Analyzing the Options**:
- **Option A: Panthera and Equus**:
- Panthera (e.g., tigers, lions) and Equus (horses) are terrestrial mammals. They have extra-abdominal testes, which are located in the scrotum outside the abdominal cavity. Thus, this option is incorrect.

- **Option B: Macaca and Macropus**:
- Macaca (monkeys) and Macropus (kangaroos) are also terrestrial mammals. They possess extra-abdominal testes. Therefore, this option is also incorrect.

- **Option C: Baleenoptera and Delphinus**:
- Baleenoptera (a genus of whales) and Delphinus (dolphins) are aquatic mammals. They typically have intra-abdominal testes, making this option correct.

- **Option D: Canis and Phallus**:
- Canis (dogs) and Phallus (cats) are terrestrial mammals with extra-abdominal testes. Hence, this option is incorrect.

3. **Conclusion**:
- The only option that correctly identifies organisms with intra-abdominal testes is **Option C: Baleenoptera and Delphinus**.

### Final Answer:
Intra-abdominal testes are found in **Baleenoptera and Delphinus**.

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