Dear Charll,
It is a known motif. You certainly know that turtle alone is an important motif in Chinese art. It represents the universe, being its carapace round as the Sky and the belly square as the Earth. Imperial stone stele was standing on a turtle representing stability due to the slow movement of the animal. Coming back to the turtle and the snake, the motif is not mentioned by Terese Tse Bartholomew in her “Hidden meanings in Chinese Art”. From the link here below, I am extracting here for ease the following:
“As there are no male tortoise -- as the ancient believed -- the female had to mate with a snake. Thus the tortoise embracing a snake became the protector symbol of the north, ……”
But I have something to show you.
Here below you can see the motif on a bronze mirror that I have. Not sure about the right period, if Tang-Song-Yuan. The mirror is full of hidden meanings, being basically the main one the representation of the four cardinal points. The turtle is the North, as said above.
The last picture is showing something unique. A water dropper of the Han dynasty that is in the Chinese museum of Parma, 60 km from where I live. One of the very few known Han pottery that is dated and signed. On the reverse is written “made by Chou San, in the fifth year of Chien An”. The Chien An period ranges from AD 196 to 220, during the reign of the last Han emperor, Hsien Ti (or Min Ti). It cames from the collection C. T. Loo.
In the book of the museum, the author says that the motif of the tortoise and the snake is representing happiness and wealth, and a powerful talisman to ward off evil. I do not know from where the Author, the deceased previous director of the museum, took this information. I only know that in writing down the catalog of the museum he has been assisted by the Chinese scholar Ye Zhemin, an authority in Chinese art.
Here is the link from where I took the meaning of the turtle and snake motif:
http://www.onmarkproductions.com/html/ssu-ling.shtmlAnd here a further link:
http://en.wikipedia.org/wiki/Black_TortoiseKind regards
Giovanni