This is the sketch you saw before. Did you think that this man is functioning as a pack horse? Now imagine what it would be like if Homer could draw the man's abdomen as the horse's head you saw in the previous slide. What a perfect supplement that would be to the theme. A horse head could function to suggest that this man was a kind of pack horse.
Think about that before you look at the finished product published in Harpers, but a moment of diversion to provide some significant background regarding Homer and his friends.