Series of channels, formed of bones are filled with

Answer

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks about a series of channels formed of bones and what they are filled with. This indicates we are looking for a specific fluid associated with a bony structure in the body.

2. **Identifying the Structure**: The channels formed of bones refer to the bony labyrinth, which is a structure found in the inner ear. The bony labyrinth consists of a series of interconnected channels.

3. **Determining the Fluid**: The fluid that fills the bony labyrinth is known as perilymph. This is an important extracellular fluid that plays a role in the function of the inner ear.

4. **Location of Perilymph**: Perilymph is specifically found within the inner ear, particularly in the scala tympani and scala vestibuli sections of the cochlea. These structures are crucial for hearing and balance.

5. **Conclusion**: Therefore, the series of channels formed of bones are filled with perilymph.

### Final Answer:
The series of channels formed of bones are filled with perilymph.

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