There can be no question that the articles in the codices on which the trembling cross is found consists, in most instances, if not all, of stone. Hence it is a reasonable conclusion that the primary signification of the symbol is stone. The Zotzil name for "flint" (pedernal) is _zuiton_. I am inclined to believe that the symbol is derived from a conventional form used for indicating stone or flint, probably from the cracks or fissures in it. I am not prepared yet to discuss the somewhat similar figures which assume the form of the St Anthony cross. Various interpretations, as symbol for "union," "night sun," etc, have been given. However, as this form is never used as a day symbol, it has no direct relation to the present discussion. THE NINETEENTH DAY Maya, _cauac_; Tzental, _cahogh_; Quiche-Cakchiquel, _caok_, _cook_; Zapotec, _ape_, _appe_, _aape_; Nahuatl, _quiahuitl_. The various forms of the symbol of this day are shown in plate 37-48--that by Landa at 37; those of the Troano and Cortesian codices at 38-43, and those from the Dresden Codex at 45-47. The irregular form given at 44 is from Tro. 28d, and that at 48 from the Peresianus. This symbol is found quite frequently in combination with other characters, in some of which its phonetic value can be ascertained with reasonable certainty. For example, it forms the lower half of the symbol for the month _Yax_, as seen at LXIV, 12; also in the symbol for the month _Zac_ (LXVI, 48). In both these instances its chief phonetic element appears to be the guttural sound _k_, or _ks_. The essential elements are also found frequently on objects which are undoubtedly of wood and where no reasonable explanation can be given except that it signifies "wood" in these places. For example, it is found on what appear to be boards carried in the hands of individuals, on Tro. 32*b (LXVII, 49); and it also is seen on what appear to be wooden boxes or gums from which the honeycomb is being removed, as Tro. 5*c and 9*a. Dr Seler, who gives quite a different interpretation of the character from that presented here, admits that these are boards. It is also found on trees, as Tro. 15*a (shown in LXVIII, 1) and 17*a, and Dres. 26c, 27c, and 28c. It is marked on the walls of houses or canopied seats, as Tro. 6b, 29*c, and 18*b. Under the last mentioned we observe the _cab_ symbol, showing that it is a building placed on the ground and not on a stone foundation. It also appears on the ends of beams, as at Tro. 9a and 22*a. True, Dr Seler contends that these are stones instead of weight poles, but I think all trappers will decide against him. Again, it appears on seats (Tro. 13a and 14*a) and also marked on heads, one of which is shown in LXVIII, 2. That the symbol is not intended to indicate the different articles on which it is found is evident; hence it must be given to denote the substance of which these things are formed, which I maintain can only be wood. That the trees and boards must be wood is