THE GORILLA 19 flat-footed at all ages, while the gorilla rarely walks upright, except in infancy. In the structure of the brain the orangs are most like man; but in other respects, in the arms and hands and feet, and in the THE GORILLA jaws, the chimpanzees are so tnuch closer to the human type that it is usual to begin with them. There are two living species of chimpanzee now recognised, zzger (the black) and caluus (the bald), B2