"First, the occipital foramen being situated entirely at the base of the cranium of man and not carried up behind, as in the other vertebrates, causes his head to be posed at the extremity of the vertebral column as on a pivot, not bowed down forward, his face not looking towards the ground. This position of the head of man, who can easily turn it to different sides, enables him to see better a larger number of objects at one time, than the much inclined position of the head of other mammals allows them to see. "Secondly, the remarkable mobility of the fingers of the hand of man, which he employs either all together or several together, or each separately, according to his pleasure, and besides, the sense of touch highly developed at the extremity of these same fingers, enables him to judge the nature of the bodies which surround him, to recognize them, to make use of them--means which no other animals possess to such a degree. "Thirdly, by the state of his organization man is able to hold himself up and walk erect. He has, for this attitude which is natural to him, large muscles at the lower extremities which are adapted to this end, and it would thus be as difficult to walk habitually on his four extremities as it would be for the other mammals, and even for the _Quadrumana_, to walk so habitually erect on the soles of their feet. "Moreover, man is not truly quadrumanous; for he has not, like the monkeys, an almost equal facility in using the fingers of his feet, and of seizing objects with them. In the feet of man the thumbs are not in opposition to the other fingers to use in grasping, as in monkeys, etc. "I appreciate all these reasons, and I see that man, although near the _Quadrumana_, is so distinct that he alone represents a separate order, belonging to a single genus and species, offering, however, many different varieties. This order may be, if it is desired, that of the _Bimana_. "However, if we consider that all the characteristics which have been cited are only differences in degree of structure, may we not suppose that this special condition of organization of man _has been gradually acquired at the close of a long period of time, with the aid of circumstances which have proved favorable?_[195] What a subject for reflection for those who have the courage to enter into it! "If the _Quadrumana_ have not the occipital opening situated directly at the base of the cranium as in man, it is assuredly much less raised posteriorly than in the dog, cat, and all the other mammals. Thus they all may quite often stand erect, although this attitude for them is very irksome.