These amazing horses are from Ulisse Aldrovandi.

The first is based on the popular legend that Julius Caesar’s favourite horse had human hands on its forelegs instead of hooves.  There was apparently a statue of this horse in front of the Temple of Venus Genetrix, sadly ruined before the invention of the camera. [x]

I don’t have an explanation for the second.  I’m not sure there is an explanation. Some things mankind was never meant to know.