Prince Ma-Ho
This "Pony-Boy" is known from a photo of his banner by Earle Caldwell, and is billed as "The World's Great Quadrumanous Entertainer." He is also possibly shown in a photo of a sideshow cast from circa 1930 (see below) where the banner calls him "Prince Eco Half." This performer suffered from "congenital genu recurvatum" – also known as "back-bending knee deformity".
Ma-Ho is also mentioned in a description of a 1925 Pathe short film in "The Exhibitor's Trade Review":