Step 1: Understanding the Concept
The limbic system lies along the inner border of the cerebrum and controls emotions, motivation and memory.
Step 2: Its parts
It includes the hypothalamus, amygdala, hippocampus and other areas, with parts of the epithalamus and thalamus.
Step 3: Find the exception
The pons varolii is part of the hindbrain. It links the medulla, midbrain and cerebellum and helps regulate breathing.
Step 4: Conclusion
Pons varolii is not a part of the limbic system.
Final Answer:
Pons varolii is the exception.
\[ \boxed{\text{(D) }\text{pons varolii}} \]