This explanation of them is not entirely new. It has previously been partly suggested by Professors Worsaae and Virchow; but the demonstration I shall offer has not heretofore been submitted to the scientific world, and its material is novel. Beginning with the Ta Ki, we find its primary elements in the symbolic picture-writing of the North American Indians. In that of the Ojibways, for example, we have the following three characters: [Illustration: FIG. 7. ] [Illustration: FIG. 8. ] [Illustration: FIG. 9. ] Of these, the Fig. 7 represents the sunrise; Fig. 9, sunset; Fig. 8, noonday. The last-mentioned is the full day at its height.[179] Where, in rock-writing or scratching on wood, the curve could not conveniently be used, straight lines would be adopted: [Illustration: FIG. 10. ] thus giving the ordinary form of the Triskeles. But the identical form of the Ta Ki is found in the calendar scroll attached to the Codex-Poinsett, an unpublished original Mexican MS., on agave paper, in the library of the American Philosophical Society. A line from this scroll is as follows: [Illustration: FIG. 11. ] Here each circle means a day, and those with the Triskeles, culminating days.[180] Another form of representing days is seen in the Vatican Mexican Codex, published in Kingsborough’s _Mexico_, Vol. iii: [Illustration: FIG. 12. ] This is not far from the figure on the stone at Copan, described in Dr. Hamy’s paper, where the design is as follows: [Illustration: FIG. 13. ] This does not resemble the Ta Ki, as Dr. Hamy supposes, but rather the Yin-Yang; yet differs from this in having a central circle (apparently a cup-shaped depression). This central circular figure, whether a boss or nave, or a cup-shaped pit, has been explained by Worsaae as a conventionalized form of the sun, and in this he is borne out by primitive American art, as we shall see. The twenty elevations which surround the stone, corresponding in number to the twenty days of the Maya month, indicate at once that we have here to do with a monument relating to the calendar. Turning now to the development of this class of figures in primitive American art, I give first the simplest representations of the sun, such as those painted on buffalo skins by the Indians of the Plains, and scratched on the surface of rocks. The examples are selected from many of the kind published by Col. Garrick Mallery.[181] [Illustration: FIG. 14. ]