(Chapter 3) Footnote 32:

The 1555 edition adds the following at this point: “Sometimes, however, in quite young children a small epiphysis occurs that is attached to this at its highest part; similarly, the entire lower part forming a portion of the joint of the forearm with the humerus, is seen by some to be formed by an epiphysis.” Both radius and ulna have epiphyses at either end.