The evolution of the mouth is particularly interesting. It is wont to begin with a horizontal line (or what seems intended for such) which is frequently drawn right across the facial circle. But a transition soon takes place to a more distinctive representation. This is naturally enough carried out by the introduction of the characteristic and interesting detail, the teeth. This may be done, according to M. Perez, by keeping to the linear representation, the teeth being indicated by dots placed upon the horizontal line. In all the cases observed by me the teeth are introduced in a more realistic fashion in connection with a contour to suggest the parted lips. The contour—especially the circular or ovoid—occasionally appears by itself without teeth, but the teeth seem to be soon added. The commonest forms of tooth cavity I have met with are a narrow rectangular and a curved spindle-shaped slit with teeth appearing as vertical lines (see the two drawings by
Fig. 6.
boys of six and five (Figs. 6, a and b). These two forms are improved upon and more likeness is introduced by making the dental lines shorter, as in Fig. 5, c. With this may be compared a drawing by a boy of five (Fig. 6, c), where, however, we see a movement from realism in the direction of a freer decorative treatment.
A somewhat similar process of evolution is noticeable in the case of the nose, though here the movement is soon brought to a standstill. Thus the vertical line gives place to an angle, which may point to the side, as in the drawing of a country boy between three and four (Fig. 7, a), but more frequently, I think, points upward, as in the drawing of a boy of six (Fig. 7, b). This in its turn leads to an isosceles triangle with an acute angle at the apex, as in the drawing of a boy of six (Fig. 7, c). In a few cases a long spindle-shaped or rectangular form similar to that of the mouth is employed, as in a drawing of a nervous child of six (Fig. 7, d). Refinements are introduced now and again by an attempt at the
