The rate of evolutionary change in a species' wing or leg or beak (remember Darwin's finches mentioned in Chapter 1?) is assessed in degree-of-physical-change units called darwins.

In control as always, he came up with a cool plan.

hatchel, hovel, gomeral

[…]and with a passing vague wonder as to what manner of man the ‘philanthropist’ might be who had more money than he knew what to do with,[…]