Modern anatomists do not divide the brain into front, middle, and occipital lobes as would seem most natural, by erecting vertical lines from their bases, but follow up the oblique courses of the convolutions so as to extend the front lobe into the upper surface of the brain, and extend the middle lobe from the middle of the upper surface backward into the region of Self Confidence, giving the name of temporo-sphenoidal to its lower portion behind the sockets of the eyes and over the ears, which name is taken from the temporal bone, that contains the apparatus of hearing, forming the middle of the basis of the skull, and the sphenoid bone, which lies just back of the sockets of the eyes, supporting the front end of the lower portion of the middle lobe, called temporo-sphenoidal. [Illustration] The sphenoid bone thus sustains the region of Sensibility, while the temporal bone lodges the organs of the most sensual, selfish, and violent impulses, the action of which is downward into the muscular and visceral organs of the body. The sphenoid bone as it extends up touches the base of the front lobe and of the Ideal region, where it assumes the name of Somnolence. (See the profile view of the cranium.) The upper portion of the middle lobe has been given the name of parietal, as it has a general correspondence with the parietal bones, while the occipital lobe has a general correspondence in position with the occipital bone, as will be seen by comparing the plan of the brain seen in profile with the engraving of the cranium. The _plan_ of the brain is given, instead of an engraving of the actual convoluted surface, to simplify the study to the learner. An examination of the brain itself or of a good model offers at first sight such a vague and irregular mass of convolutions, differing so much in different brains, that any systematic arrangement would seem impossible. But by studying the subject more extensively and considering the structure of the simpler brains of animals, in which the complexity of the human brain is reduced to simpler forms, a mode of grouping and classifying the convolutions has been adopted by anatomists which is illustrated by the engraving, in which we see, not the numerous convolutions of a well developed human brain, but the groups in which they have been arranged by the aid of comparative anatomy. The front lobe is grouped into the superior, middle, and inferior convolutions, or groups of convolutions, and the ascending frontal; but the inspection of a brain would show an irregularity of forms in which a casual observer would be puzzled to trace this arrangement.