I am inclined to believe that the design as a whole represents a sun shield, the eight radiating bars being the rays, while the celestial band, the three human figures, and the Colhuacan glyph replace the parts of the sun’s face, namely, the head-band, the two eyes and nose (the plunging figure in lieu of the nose), and the mouth. This may seem pretty far-fetched at first glance, but it is quite in the spirit of Aztec art. On the Calendar Stone, around the face of the sun god and the _ollin_ symbol with the enclosed glyphs of the four ages, is, first, a circle of the day signs, second, a circle of quincunx figures, supposed to be the classical hieroglyphs or rather symbols of turquoises, third, a frieze of eagles’ feathers. Multiple rays of different sizes complete the picture. In the actual shield before us we have the turquois mosaic, and the holes around the rim suggest that eagles’ feathers may once have been attached. Compare the sun shield or sun basket of the Pueblo Indians, and the various sun shields on Mayan monuments. Now, the sun and turquois seem to be pretty closely connected symbolically--both mean divine. The hieroglyph of the sun is used for the _teo_, god, in place names, while the prefix _xiuh_ means divine in connection with various objects. Jade, on the other hand, means precious. The sun in Aztec ritual is pretty closely connected with riches and jewels, and the sun disc may easily have been conceived of as a gem-studded object. I think it quite possible, therefore, that the design on this shield was intended to symbolize the face of the sun, and the fact that complete figures engaged in some ritualistic function replaces the parts of a realistic face does not detract from the theory. The back of the shield is shown in pl. XXII. Through the two vertical ridges are pairs of holes, evidently for the leather thongs for holding the shield. The twenty-eight small holes around the edge of the shield were probably for the insertion of feathers or other ornaments, as in the British Museum shield. In technique our shield is similar in all respects to the two mosaic shields in Europe. In all three the incrustation is in a bed of gum that has been spread over the wood.