As the car carrying Ethel enters the circus ring Finn has his top hat in his in his left hand but in the next shot it's on his head.
Far more than six shots are fired from the revolver.
Throughout the short, everyone refers to Ethel as a monkey, when she is in fact, an ape.
The picture of "Ethel" the landlord is holding, and the actress portraying her are two different people.
After Stan, Ollie, and Ethel run off screen to escape the lion, when it comes on screen there appears at the top of the frame a corner of an umbrella or awning shading the camera.
After they have managed to lure Ethel, the gorilla, inside the crate, Ollie says to Stan "get some rope and we'll tie him up" despite knowing that Ethel is female.