The head for 13 is shown in figure 52, _w-b'_. Only the first of these forms, _w_, however, is built on the 10 + 3 basis. Here we see the characteristic 3 head with its banded headdress or fillet (compare _h_ and _i_, fig. 51), to which has been added the essential element of the 10 head, the fleshless lower jaw, the combination of the two giving the head for 13. The other form for 13 seems to be a special character, and not a composition of the essential elements of the heads for 3 and 10, as in the preceding example. This form of the 13 head (fig. 52, _x-b'_) is grotesque. It seems to be characterized by its long pendulous nose surmounted by a curl (), its large bulging eye (**), and a curl () or fang (++) protruding from the back part of the mouth. Occurrences of the first type--the composite head--are very rare, there being only two examples of this kind known in all the inscriptions. The form given in _w_ is from the Temple of the Cross at Palenque, and the other is on the Hieroglyphic Stairway at Copan. The individual type, having the pendulous nose, bulging eye, and mouth curl is by far the more frequent. The head for 14 (fig. 53, _a_) is found but once--in the inscriptions on the west side of Stela F at Quirigua. It has the fleshless lower jaw denoting 10, while the rest of the head shows the characteristics of 4--the bulging eye and snaglike tooth (compare fig. 51, _j-m_). The curl protruding from the back part of the mouth is wanting because the whole lower part of the 4 head has been replaced by the fleshless lower jaw. The head for 15 (fig. 53, _b-e_) is composed of the essential element of the 5 head (the tun sign; see fig. 51, _n-s_) and the fleshless lower jaw of the head for 10. The head for 16 (fig. 53, _f-i_) is characterized by the fleshless lower jaw and the hatchet eye of the 6 head. Compare figures 51, _t-v_, and 52, _m-r_, which together form 16 (10 + 6). The head for 17 (fig. 53, _j-m_) is composed of the essential element of the 7 head (the scroll projecting above the nose; see fig. 51, _w_) and the fleshless lower jaw of the head for 10. The head for 18 (fig. 53, _n-q_) has the characteristic forehead ornament of the 8 head (compare fig. 52, _a-f_) and the fleshless lower jaw denoting 10. Only one example (fig. 53, _r_) of the 19 head has been found in the inscriptions. This occurs on the Temple of the Cross at Palenque and seems to be formed regularly, both the dots of the 9 head and the fleshless lower jaw of the 10 head appearing.