I just ran across this in the end of an article in the New York Times:
But Mrs. Clinton faces another problem there in the form of that state’s unusual delegation allocation rules. Delegates are allocated to state senatorial districts based on Democratic voter turn-out in the last election. Bruce Buchanan, a professor of political science at the University of Texas at Austin, noted that in the last election, turnout was low in predominantly Hispanic districts and unusually high in urban African-American districts.
That means more delegates will be available in districts that, based on the results so far, could be expected to go heavily for Mr. Obama.
Very interesting. Even should Texas have high turnout in areas with demographics in which Senator Clinton has traditionally done well, she may end up with fewer delegates than expected.