(Chapter 26) Footnote 10:

Phalanx proximalis, phalanx distalis. What follows, down to the reintroduction of Galen’s name several lines farther down, was largely deleted, rewritten as follows for the 1555 edition: “— and because the first bone of the thumb much more resembles the metacarpal bones in its overall shape than it does the first bones of the other fingers.” Though Vesalius pays more attention to the actual structure of the thumb than Galen had done, he remains Galenic (contrary to both ancient and modern anatomical opinion) in preferring a unique structure for the thumb to one that recognizes the formal symmetry of hand and foot. See Siraisi 1997 p. 7 and Michler 1964 pp. 200-15.