Does Levi-Strauss directly equate mythology with exogamy at all? If women represent signs for communication that are to be exchanged outside of a group, then they're used as links to a social world. Myth appears to work similarly in that it is constructed to meet a communication goal, in this case rationalization. Both are further equated with language (though perhaps speech or discourse would be a better term) in that they contain elements that on their own are insignificant but gain meaning when all elements are viewed as a whole.

However, Levi-Strauss rejected the notion that myths serve primarily social functions and were instead logical, while exogamy and the incest taboo do seem social (though perhaps not in construct--can a social function originate from a universal construct?) Do mythology and exogamy serve similar purposes despite their apparently different (to me) goals?

On another note, where do other rationalizations against the incest taboo fit into Levi-Strauss' proposal, even if they are not universal as he claims the exogamy rationalization is?