In a subsequent paper, Welcker states that the absence of the round ligament in the orang-utan, and its presence in the chimpanzee, had been previously established by Camper and Owen.[64] In three specimens of orangs which he had obtained immediately after death, Owen found that the round ligament was imperfectly developed on both sides. The chimpanzee differs from the orang in possessing a depression on the head of the femur. In the gorilla, as Owen observes, this depression has almost the same depth and relative position as in man. At Welcker’s request, Professor Dippel ascertained the presence of the depression in the femur of a gorilla skeleton which is preserved in the natural history collection at Darmstadt. St. George Mivart saw the skeleton of an orang in which the femur was marked with a slight but plainly indicated depression, just where the round ligament is usually attached. Welcker thinks it probable that in some specimens of the gorilla the round ligament is only slightly developed, and that in others it is altogether wanting. On several femurs of gorillas, this naturalist observed only doubtful traces of the depression in question. Duvernoy found the round ligament fully developed in the gorilla and chimpanzee. Vrolik failed to find it in the orang-utan, but ascertained its presence in the chimpanzee. Gratiolet and Alix saw that it was fully developed in _Troglodytes Aubryi_. In addition to these somewhat conflicting assertions, I have myself observed, in the gorilla innominate and femur bones examined by me, more or less distinct indications of the depression which receives the round ligament. The ligament itself has been preserved with the body of a gorilla. The same remark applies to the skeletons and bodies of chimpanzees. In the case of the skeleton of an orang, slight indications of a depression were observed on the head of the left femur, and these indications were absent in the femurs of other specimens. In a large orang-utan which died in the Berlin Aquarium, only short, filamentous tufts of streaky fibres were apparent in the right acetabulum, and these were intermingled singly or in groups with the cartilaginous cells, somewhat resembling the cartilaginous corpuscles of the synovial membrane. From these facts we may conclude that the round ligament is generally but not invariably present in the gorilla and chimpanzee, and that it is altogether absent in the orang-utan. In the gibbon it is present in the majority of cases. I have myself observed it in _Hylobates agilis_, _leuciscus_, and _syndactylus_. Owen asserts that the unsteady gait of the orang is partly due to the absence of this ligament, but the truth of this surmise is rendered doubtful by the fact that the ligament is not unfrequently absent in other anthropoids. Moreover, the gait of all these arboreal and climbing animals is extremely ungainly.