[20], p) are again identical in each case. The signs for the next month, Mac, however, are entirely dissimilar, the form commonly found in the inscriptions (fig. [19], w) bearing absolutely no resemblance to that shown in figure [20], q, r, the only form for this month in the codices. The very unusual variant (fig. [19], x), from Stela 25 at Piedras Negras is perhaps a trifle nearer the form found in the codices. The flattened oval in the main part of the variant is somewhat like the upper part of the glyph in figure [20], q. The essential element of the glyph for the month Mac, so far as the inscriptions are concerned, is the element (*
) found as the superfix in both w and x, figure [19]. The sign for the month Kankin (figs. [19], y, z, and [20], s, t) and the signs for the month Muan (figs. [19], a', b', and [20], u, v) show only a general similarity. The signs for the last three months of the year, Pax (figs. [19], c', and [20], w), Kayab (figs. [19], d'-f', and [20], x, y), and Cumhu (figs. [19], g', h', and [20], z, a', b') in the inscriptions and codices, respectively, are practically identical. The closing division of the year, the five days of the xma kaba kin, called Uayeb, is represented by essentially the same glyph in both the inscriptions and the codices. Compare figure [19], i', with figure [20], c'.
It will be seen from the foregoing comparison that on the whole the glyphs for the months in the inscriptions are similar to the corresponding forms in the codices, and that such variations as are found may readily be accounted for by the fact that the codices and the inscriptions probably not only emanate from different parts of the Maya territory but also date from different periods.
The student who wishes to decipher Maya writing is strongly urged to memorize the signs for the days and months given in figures [16], [17], [19], and [20], since his progress will depend largely on his ability to recognize these glyphs when he encounters them in the texts.
The Calendar Round, or 18980-day Period
Before taking up the study of the Calendar Round let us briefly summarize the principal points ascertained in the preceding pages concerning the Maya method of counting time. In the first place we learned from the tonalamatl (pl. [5]) three things: (1) The number of differently named days; (2) the names of these days; (3) the order in which they invariably followed one another. And in the second place we learned in the discussion of the Maya year, or haab, just concluded, four other things: (1) The length of the year; (2) the number, length, and names of the several periods into which it was divided; (3) the order in which these periods invariably followed one another; (4) the positions of the days in these periods.
The proper combination of these two, the tonalamatl, or "round of days," and the haab, or year of uinals, and the xma kaba kin, formed the Calendar Round, to which the tonalamatl contributed the names
of the days and the haab the positions of these days in the divisions of the year. The Calendar Round was the most important period in Maya chronology, and a comprehension of its nature and of the principles which governed its composition is therefore absolutely essential to the understanding of the Maya system of counting time.
It has been explained (see p. [41]) that the complete designation or name of any day in the tonalamatl consisted of two equally essential parts: (1) The name glyph, and (2) the numerical coefficient. Disregarding the latter for the present, let us first see which of the twenty names in Table [I], that is, the name parts of the days, can stand at the beginning of the Maya year.