952 NUMERAL SYSTEMS (ETH. ANN. 19 
calendars seven days painted with black figures, the first beginning 
with a Friday. This period was, however, probably based on the 
European week. That 7 would appear in the adjustment of the thirteen 
series to the twenty days of the month is evident; it is also noticeable 
that in some of the Mexican codices where the space is not sufficient to 
place thirteen day-symbols in a single series, where series of this length 
are referred to, the division is usually, though not always, into seven 
and six. However, the necessity of referring to seven in these instances 
does not appear to have brought it into use as a counter. Its appear- 
ance, therefore, in the time system and time count may be considered as 
accidental, or at least without significance. Nevertheless it does appear 
occasionally in relations where its use seems to be mystical. From 
the earliest times, the Cakchiquel, with perhaps others with whom 
they were related, are mentioned in their annals as ‘*seven tribes” 
or seyen villages arranged in thirteen divisions. Their sacred days 
were the seventh and the thirteenth. Tradition brings the ancestors 
of the Mexicans from seven caves; they come as seven tribes, the 
descendants of seven brothers. Among their gods was a deess named 
Centeocihuatl, also called Chicomecohuatl or the ‘‘Seven Serpents,” 
who, it is said, nourished the seven gods who survived the flood. It is 
said in the Quiche legend (Popul Vuh) that Gucumatz, their great 
culture hero, ascended each seven days to heaven, and in seven days 
descended into Xibalba; that for seven days he took the form of a ser- 
pent; seven others that of an eagle; seven others that of a tiger, and 
seven others that of coagulated blood, as has been already mentioned. 
Among their mythical heroes was Vukub-Cahix (**Seven Aras”), and 
the ruler of Nibalba was Vukub-Came (‘‘Seven Deaths”). 
The number 9, though seldom referred to in the ceremonials and 
mysteries, was not without a place therein among the Mexicans. 
They recognized nine ‘‘ Lords of the Night.” These are evidently 
referred to in the Borgian codex, as in the Tonalamatl, plates 31 to 38, 
where they are marked by footprints, and on plate 75, where the night 
is symbolized by the large black figure and the nine lords by nine 
star-like figures. It is stated in the Explanation of the Codex Tel- 
leriano-Remensis that he who was born on the day 9 Ehecatl would be 
prosperous as a merchant, while he who was born on the day 9 Itzeuintli 
would be a great magician. The Mexicans also recognized nine 
heavens. This number appears also to have had some significance 
among the Quiche, as they held that in each month there would be 
nine good and nine bad days, and two indifferent. 
Next to 20, 13 was the most important number in the time systems 
of Mexico and Central America. Not only was it the number of days 
in their so-called week, but it was that by which the days were num- 
bered. Although it did not form one of the regular time periods, as 
