In the gorilla a faint depressor anguli oris and an equally faint depressor labii inferioris may be observed, the latter partly covered by the large and predominant orbicularis oris (Fig. 50). In the chimpanzee the two depressors are plainly apparent, and in the gibbon the one first named was at any rate developed. The platysma myoides, the depressors just mentioned, and the crescent-shaped orbiculares are in this animal in close connection with each other. Froriep’s suggestion becomes ever more probable, that these muscles of the lower lip owe their origin to the intersection of the opposite portions of the skin-muscles of the neck which overlap the face. The buccinator muscle in anthropoids resembles on the whole that of man, and in both cases is pierced by Stenson’s duct (Fig. 50). The form of the masseter muscle is common to both (see Fig. 50, ~11, 16~). In the external ear of anthropoids there is an attrahens, attollens, retrahens (Fig. 50). Compared with that of a white man, and still more with that of a negro (see Figs. 48, ~19~, and 49, ~17~), the attollens is only slightly developed. The muscles attached to the cartilages of the ear are extremely scanty or partially wanting, which is also sometimes the case with man. The muscles of the helix are most strongly marked in the gorilla (see, for example, Fig. 50, ~21~). Tiedemann, Bischoff’s brother-in-law, carefully observed two living chimpanzees in Philadelphia for six months without detecting any movement of the ears. My own observation confirms his assertion and the remarks of Darwin, which I have already quoted, to the effect that anthropoids are incapable of moving their ears. I know of no individual exceptions. This is the more remarkable since some men have retained the power of voluntarily moving their ears, and the same power is also found in some species of apes, such as the sea-cats, baboons, macacas, and magots. It will not here be out of place to say something of the characteristics, previously mentioned, of the physiognomical expression of anthropoid apes. Thus, for example, when the gorilla is agitated, he can move the skin of his head and bristle the hair which covers this region. The chimpanzee can also move the skin of the head, but with no very apparent bristling of the hair. The large male orang, which was in the Berlin Aquarium in 1876, bristled his hair and the skin of his head when he was much enraged. It is known that in some instances man also possesses this power. I have already spoken of the expression of the eyes of these animals. I will only add that when anthropoids of every species are in great pain or seriously ill, the expression of their eyes is often most affecting.