Then there is a connection between Wega and the turtle - which (as I believe) is represented in GD17:

"Among Latin writers it was Lyra, in classical times as in later ... its preëminent brightness fully accounting for the usurpation of so many of its constellation's titles, indeed undoubtedly originating them."

"Aratos called it [the constellation Lyra] Χέλυς όλίγη, the Little Tortoise or Shell, thus going back to the legendary origin of the instrument from the empty covering of the creature cast upon the shore with the dried tendons stretched across it.

Lowell thus described its discovery and use by Hermes:

So there it lay through wet and dry, / As empty as the last new sonnet, / Till by and by came Mercury, / And having mused upon it, / 'Why, here' cried he, 'the thing of things / In shape, material and dimension! / Give it but strings and, lo! it sings - / A wonderful invention'."

"The Leyden Manuscript has the conventional instrument, with side bars of splendid horns issuing from the tortoise-shell base; the Venetian Hyginus of 1488, with a similar figure, calls it Lura as well as Lyra; but the drawing of Hevelius shows 'an instrument which neither in ancient nor in modern times ever had existence'. Dürer's illustration, as well as others, places it with the base towards the north." (Allen)

So it was upside down. Mercury reminds me of how he won 5 extra days from the Moon in a game of checkers, those dark days which presumably belong to the gods of the mountain. Furthermore, the irregular orbit of Mercury may have connected him with Huwawa/Humbaba, the God of Intestines, which remarkably seems to have an echo among the Eskimo, where there are stories about the 'Entrail Snatcher'.