is an enchanted thing (1)
This first line is packed with meaning. In order for anything to be enchanted, it has to be aware. To put it another way, how can you be enchanted by something if you aren't conscious of its existence? In line one, we're already talking consciousness.
till the nettings are legion. (5)
Think of this as an example of things all coming together for some clarity, like an "ah-ha!" moment.
It has memory's ear (13)
The mind seems to be aware of all moments in time: thinking back to the past, being present in the moment, and imagining the future.