The head for 8 is shown in figure 52, _a-f_. It is very similar to the head for 1, as previously explained (compare figs. 51, _a-e_ and 52, _a-f_), and is to be distinguished from it only by the character of the forehead ornament, which is composed of but a single element (). In figure 52, _a_, _b_, this takes the form of a large curl. In _c_ of the same figure a flaring element is added above the curl and in _d_ and _e_ this element replaces the curl. In _f_ the tongue or tooth of a grotesque animal head forms the forehead ornament. The heads for 18 (fig. 53, _n-q_) follow the first variants (fig. 51, _a_, _b_), having the large curl, except _q_, which is similar to _d_ in having a flaring element instead. The head for 9 occurs more frequently than all of the others with the exception of the zero head, because the great majority of all Initial Series record dates which fell after the completion of Cycle 9, but before the completion of Cycle 10. Consequently, 9 is the coefficient attached to the cycle glyph in almost all Initial Series.[69] The head for 9 is shown in figure 52, _g-l_. It has for its essential characteristic the dots on the lower cheek or around the mouth (). Sometimes these occur in a circle or again irregularly. Occasionally, as in _j-l_, the 9 head has a beard, though this is not a constant element as are the dots, which appear also in the head for 19. Compare figure 53, _r_. The head for 10 (fig. 52, _m-r_) is extremely important since its essential element, the fleshless lower jaw (), stands for the numerical value 10, in composition with the heads for 3, 4, 5, 6, 7, 8, and 9, to form the heads for 13, 14, 15, 16, 17, 18, and 19, respectively. The 10 head is clearly the fleshless skull, having the truncated nose and fleshless jaws (see fig. 52, _m-p_). The fleshless lower jaw is shown in profile in all cases but one--Zoömorph B at Quirigua (see _r_ of the same figure). Here a full front view of a 10 head is shown in which the fleshless jaw extends clear across the lower part of the head, an interesting confirmation of the fact that this characteristic is the essential element of the head for 10. The head for 11 (fig. 52, _s_) has been found only once in the inscriptions, namely, on Lintel 2 at Piedras Negras; hence comparative data are lacking for the determination of its essential element. This head has no fleshless lower jaw and consequently would seem, therefore, not to be built up of the heads for 1 and 10. Similarly, the head for 12 (fig. 52, _t-v_) has no fleshless lower jaw, and consequently can not be composed of the heads for 10 and 2. It is to be noted, however, that all three of the faces are of the same type, even though their essential characteristic has not yet been determined. {101}