The Egyptian Book of the dead by P. Le Page Renouf and Edouard Naville

the name of the mythological serpent which personifies the subterranean path from West to East of the Sun’s nightly course. In the _Book of Hades_ (_e.g._ on the Sarcophagus of Seti, _passim_) it is represented as extending over the back, top and front of the shrine in which the Sun-god is borne in his Bark. The many folds of the serpent are symbolical of the turnings and windings of the river or canal (⁂) over which the god is conveyed. This river is here described as infinite in length. This is one of the instances from which it is clear ⁂⁂⁂, like the corresponding Coptic ⲟⲩⲉⲓ, has the meaning of _length_. See _P.S.B.A._, XVII, 190. The length ‘from West to East’ is described as ‘from _Amur_ to _Taur_’ ⁂⁂⁂⁂⁂⁂⁂⁂⁂. _Amur_ is known from many texts to signify the West (see _supra_, Chapter 64, note 13). The East is known as _Ta-ur_ or _Ta-urit_. The royal Ritual at Abydos (Mariette, I. 37) says ⁂⁂⁂⁂⁂⁂⁂⁂⁂⁂⁂⁂. And as one of the values of the sign ⁂ is _ta_ as in ⁂⁂ (Louvre, B. 14), I feel sure that we should read _Ta-ur_ (or in the feminine _Ta-urit_) rather than _Nif-ur_ or _Nif-urit_, even in such passages as those quoted _supra_ in Chapter 128, notes 1 and 2, which have no necessary references to earthly geography.