<<I understand the serpent symbol as it relates to the structure of matter to represent this coiled membrane. >>
Could it also by relating to the "structure of matter" represent the circuit of light, in and from matter, the so-called alchemy? Observing the pyramid in Mexico at the spring equinox, shadows are cast on the steps of the pyramid that give the appearance of a serpent descending from the Sun - and it projects 7 isosceles triangles on the steps. As the sun descends, there is a slow undulation as the serpent returns. This is one connection with the sky - sky gods are regularly depicted with wings. On the other hand the ureaus at the pharaoh's brow is the serpent (light)raised, from the sleep in matter and illuminating the psychic center bringing cosmic consciousness.
The lurking "darkness" may be nothing else but collective fearful thoughts deposited on the astral plane.