Birds, Reptiles, Mammals, Amphibians all have the same Humerus, Ulna + Radius, Metacarpals, phalanges as it this line of fish they evolved.
The same structure is on all four limbs.
This is discovered by Oken in Germany. He was publicly educated years before the system evolved in Britain. He basically guess evolution before Darwin, and said the skull was a special backbone, which seems reasonably correct.
