The philosophical underpinnings are there I think. Besides, Augustine postulated just such a process at work with flies and other creatures which he thought were created potentially and not actually during the hexamaeron.
So now you're going to fall back on an actual erroneous belief, biogenesis, in order to defend evolution? Smart move.
As I understand it, Augustine did not teach that things "evolve" but that everything was created at once in the first instant. This constituted the problem with the six days in his eyes.
Ha! Well, no I am not actually. The scientific methodology he used was partly wrong, I get that. I'm more interested in the *philosophical principle* he was defending, which was that creation of potential was wholly within Christian revelation. (Incidentally, I say partly because the scientist who disbelieves miracles is constrained to admit that abiogenesis happened at least once.)
As I understand it, Augustine did not teach that things "evolve" but that everything was created at once in the first instant. This constituted the problem with the six days in his eyes.
You understand more or less correctly, however he was not dogmatic about it, he was just offering his opinion. From what I read he certainly didn't give credence to the idea that the animals created in types could become other types. However, again philosophically speaking, his arguments from abiogenesis and on the phases of the moon show he wasn't opposed to the notion that God created things potentially which would come to perfection later.