I think there can be little doubt that the symbol, as has been suggested by others, was taken from the full face, the central double line representing the nose, the two open dots the eyes, and the circle below the mouth. Now, according to Fuller's Zapotec Vocabulary, the name for face is _lu_, which is the Zapotec name of the day. As has been stated, Dr Brinton thinks the Nahuatl and Zapotec names refer to the sun, and he is inclined also to believe that the "ruler" or "sovereign" referred to by the names of the Maya dialects is the sun.
I think we may rest assured that the symbol of this day was derived from the full face, and that the word (for face) it was intended to indicate had _l_ as its chief phonetic element--possibly from _lec_, "brow, front, forehead." If derived from the face, its use as a day symbol, and in numerous combinations, proves beyond question that it is phonetic in the true or in the rebus sense.
[205-1] Study of the Manuscript Troano, pref., p. viii.
[205-2] American Anthropologist, Washington, July, 1893.
[207-1] The plates are designated by Roman numerals, and the figures by the Arabic numbers 1, 2, 3, etc. Hence LXIV, 1, signifies figure 1 of plate LXIV; LXIV, 2, figure 2 of plate LXIV, etc.
[208-1] American Anthropologist, July, 1893, p. 254.
[208-2] There appears to be much confusion among writers who have referred to this subject in regard to the "Black Deities" of the codices. Dr Brinton's remarks on this subject in his late work, "A Primer of Mayan Hieroglyphics," does not clear up the confusion. Apparently he has not discovered that quite a number of these are merely black figures of well-recognized deities not thus usually colored. It appears also, judging by his statements, that Dr. Brinton has failed to identify the characteristics by which the different deities of this class are to be distinguished. Dr Schellhas, in his excellent paper "Die Gottergestallen der Maya Handschriften," fails also to properly distinguish between these deities. Dr Seler, whose profound studies have thrown much light on the Maya hieroglyphs, fixes quite satisfactorily the characteristics of some of these deities, yet he confounds others which should have been separated.