(Chapter 33) Footnote 74:

For this comparison, cf. Galen De usu partium 3.203.16-204.2: “Certainly it is not hard to see the resemblance in construction between the carpus and the tarsus. The tarsus is composed of four bones and the carpus of double that number, since it is arranged in two rows; for it is characteristic of prehensile instruments to be made up of a large number of small parts, whereas instruments of locomotion have larger parts and fewer of them.” (tr. May 1968, p. 171).