The head and face in the middle of the monument conveys the idea of duality, being masked, _i. e._ doubled-faced and bearing the number 2 carved on its forehead. It conveyed the conception of a divine power who ruled heaven and earth from a changeless and fixed centre in the heaven; expressed the dual government of the earth by twin-rulers who dwelt in a central capital. It typified light and the heaven itself with its two eyes; the sun and moon and darkness and the earth by the mouth; whilst the symbols for breath issuing from both nostrils and the tongue protruding from the mouth denoted the power of speech, which was so indissolubly connected with the idea of chieftainship by the Mexicans that a title for the chief was “the Speaker.” The central head likewise denoted a “complete count”=one man, and was expressive of a great era of time, embodying twenty epochs. As a synopsis of the whole, the following titles recorded in the chronicles would be applicable to the central ruler, celestial or terrestrial: the two lord, the divine twin; the two-lord and two lady; the quadruple lord, “He who looks in four directions;” the lord of the thirteen powers; the one lord, _i. e._ embodying a complete count=20; the lord of five (_i. e._ of the Middle and Four Quarters); of seven, _i. e._ of the Middle, Above, Below, and Four Quarters; of thirteen, _i. e._ of the duplication or male and female or celestial and terrestrial divisions of the Above, Below and Four Quarters plus the Middle. Surrounding the central head are four square divisions arranged in two separate parts, each of which includes what appears to be in one case the right, and in the other the left, conventionalized claw (forepaw?) of an animal armed with hooked nails, such as Mictlantecuhtli, the lord of the North, is represented with. The square compartments contain symbols of the four elements so disposed that air and water are appropriately associated with the hand to the right (=male region) and fire and earth with the hand to the left side (=the female region) of the central head. But this is not all, for another carefully devised relation between the elements likewise appears upon careful examination. In the middle, carved above the central face and between the symbols for air and fire, is the conventionalized “ray of the Sun,” or pyramid which typifies “that which ascends or is above” the upper elements and the Above. As its opposite we find below, situated between the symbols of earth and water, a ring with a concentric circle representing the drop of water=“that which descends.” As the Moon was inseparably associated with water and the Below, it is doubtlessly included in the symbolism.