Dąbrowski has an unidentified “Symbols of the Ancient and Accepted Scottish Rite”, see below left. Judging the text in the triangle, it is from France. The 25th degree of the AASR is the Knight of the Brazen Serpent and its emblem can be seen below. An image more like the one above can be found on some 25th degree AASR tracing boards.
Would the Cross with Snake be a variation to this symbol?
A snake around a T(au) cross can also be found on the tracing board of the 49th degree (“Sublime Sage of the Pyramids”) of (some variations of) Memphis Misraim.
Top and left: Dąbrowski P. 212 (“Symbols of the Ancient and Accepted Scottish Rite”). Year and designer unknown.
Bottom right: general AASR officer jewel