The five normæ, or aspects of the human skull, viz.:—(B) Norma verticalis, the vertex view; (C) Norma lateralis; (D) Norma facialis; (E) Norma basilaris; (A) Norma occipitalis.] 7. The _lower jaw_ is studied independently. The prominence of the chin, the squareness of the angle, the stoutness of the whole bone, and the number and characters of the teeth are the chief points to which attention is directed. [Illustration: FIG. 2.—Measurement of the length of the skull with callipers (Flower’s Craniometer as modified by Dr. Duckworth). FIG. 3.—Measurement of the length of the skull with another form of callipers.] 8. _Cranial measurements_ are made with callipers and a flexible steel or tape measure. These objects, as well as a graduated two-meter rod used for measuring stature or long bones, are supplied in a travelling case by Messrs. Hermann of Zürich, who have made them to Professor Martin’s designs. The whole outfit costs about £4, but the instruments can be obtained separately. Messrs. Hermann also make a modified form of the callipers, known as Flower’s Craniometer (cf. Fig. 2). Measurements are recorded in millimeters, in which the various callipers, etc., are graduated. The latter instruments may have the forms represented in Fig. 2 (Flower’s Craniometer) or Fig. 3, in which are shown the exact positions of the instruments in measuring the length of the skull. The chief measurements may be now enumerated in order of importance:— i. The _extreme length_ of the brain-case, measured as shown in Figs. 2 and 3. ii. The _maximum breadth_ of the skull is measured on the brain-case. iii. The _circumference_ of the brain-case (as distinct from the face) is measured with the flexible tape passed round the brow-ridges and the back of the skull. The measurement is that of the greatest circumference of the brain-case obtainable in this way. iv. Measurements illustrative of the degree of prominence of the upper jaw are two in number, and are made with the callipers. The two measurements start from the same point behind; this point is the middle of the front edge, or margin, of the hole for the spinal cord (foramen magnum), shown in Fig. 1, E. From this common point, the upper or _basi-nasal measurement_ passes to the upper border of the nasal bones in the middle line of the face, and the lower or _basi-alveolar measurement_ passes to the extreme front edge of the upper jaw in the middle line, just above and between the upper incisor teeth.