The nerves which pass out through the foramina in the base of the skull must be considered separately, as the function of each of them shows some peculiarity. Some are exclusively nerves of special sense, some are simple, being purely motor in function, while others are exceedingly complex, containing many kinds of fibres. They may be taken in the order of their functional relationships, motor and mixed. Those which relate to the special senses will be considered in future chapters.