It is Johanna the female Chimpanzee which the circus obtained in 1893. They already had Chiko, who they correctly identified as a Chimpanzee. Barnum knew quite well that Johanna was a Chimpanzee, but labelled her as either a "black orang" or a Gorilla because there were no live Gorillas in captivity at this point (there had been a few very short-lived babies in Europe before this; the first to arrive in America wasn't until 1897).