The principal points to be considered under each of these heads are the following: I. THE GENERAL FORM. 1. The size of the head. 2. The squareness or slope of the shoulders. 3. The length of the arms. 4. The constriction of the waist. 5. The width of the hips. 6. The length of the leg, principally of the thigh. 7. The sizes of the hands and feet. 8. The relative sizes of the muscles. [Illustration: FIG. 4.--Portrait of a girl at five years of age.] II. THE SURFACES. 9. The structure of the hair (whether curled or not). 10. The length and position of the hair. 11. The size and shape of the nails. 12. The smoothness of the skin. 13. The color of the skin, hair, and irides. [Illustration: FIG. 5.--Portrait of the same at seventeen years, showing the elongation of the facial region, and less protuberance of the cerebral.] III. THE HEAD AND FACE. 14. The relative size of the cerebral to the facial regions. 15. The prominence of the forehead. 16. The prominence of the superciliary (eyebrow) ridges. 17. The prominence of the alveolar borders (jaws). 18. The prominence and width of the chin. 19. The relation of length to width of skull. 20. The prominence of the malar (cheek) bones. 21. The form of the nose. 22. The relative size of the orbits and eyes. 23. The size of the mouth and lips. [Illustration: FIG. 6.--Profile of a Luchatze negro woman, showing deficient bridge of nose and chin, and elongate facial region and prognathism.] The significance of these, as of the more important structural characters of man and the lower animals, must be considered from two standpoints, the paleontological and the embryological. The immediate paleontological history of man is unknown, but may be easily inferred from the characteristics displayed by his nearest relatives of the order Quadrumana. If we compare these animals with man, we find the following general differences. The numbers correspond to those of the list above given: I. _As to General Form_.--(3) In the apes the arms are longer; (8) the extensor muscles of the leg are smaller. II. _As to Surface_.--(9) The body is covered with hair which is not crisp or woolly; (10) the hair of the head is short; (18) the color of the skin, etc., is dark. III. _As to Head and Face_.--(14) The facial region of the skull is large as compared with the cerebral; (15) the forehead is not prominent, and is generally retreating; (16) the superciliary ridges are more prominent; (17) the edges of the jaws are more prominent; (18) the chin is less prominent; (20) the cheek bones are more prominent; (21) the nose is without bridge, and with short and flat cartilages; (22) the orbits and eyes are smaller (except in Nyctipithecus); (24) the mouth is small and the lips are thin. [Illustration: FIG. 7.--Face of another negro, showing flat nose, less prognathism and larger cerebral region. From Serpa Pinto.]