Dear Don Barone,
Thanks so much for your entry, this is really interesting! I have come across many versions of the Shepherds of Arcadia and only one or two are full of symbolism, while the others are just the Shepherds of Arcadia or even gods and goddesses in their place!! It is incredible how Poussin has involved symbolism in his paintings. Take a look at http://www.languedocvakantie.nl
and click onto the English flag and then go to the page La Madeleine and the Mysticism. At the bottom you will also see a Poussin painting with an interesting twitch!
Lotsa love and hope to hear from you soon!