With regard to the connection of the Pleiades with the beginning of the Mexican cycle, it is interesting to note Herr Andree’s statements that the most intimate connection of the star-group with the thoughts of primitive people, would naturally take place in such localities where its periodical movements coincided with the changes of season, wind and weather which affected agriculture. A survey of the data presented by Herr Andree shows that the cult of the Pleiades attained its greatest development amongst tribes inhabiting a southerly latitude. It was in South America, indeed, that the Peruvians, alongside of their highly developed sun-cult, rendered homage and offered sacrifices to the Pleiades. In Mexico, the cult of the Pleiades appears as intimately associated with that of the sun and to have assumed importance only in historical and comparatively recent times, probably when the periodicity of the sun’s movements had been taught or recognized and the sign _ollin_, which is an exact presentation of the annual course of the sun, had been invented and adopted as a symbol. I have already pointed out that this sign occurs on the calendar-stone, for instance, which has a human face in its centre, bearing two numerals on the forehead and obviously symbolizing the union of two in one. In other instances the centre displays the eye, or star symbol and conveys the suggestion that the “four movements” of the circumpolar constellations were thereby symbolized. It may be that, in ancient Mexico, the two symbols, respectively referring to the movements of the sun and of the circumpolar star-groups, were emblematic of the two different cults or religions which existed alongside of each other. The first, the cult of the Above, of the Blue Sky, was directed towards the sun and the planets and stars intimately associated with sunrise and sunset, amongst them the Pleiades. The cult of the Below, of the Nocturnal Heaven, was directed towards the moon, Polaris and the circumpolar constellations—also to the stars and planets during the period of their disappearance and possibly in the same way to the enigmatical “Black Sun,” figured in the B. N. MS. which may have been the sun during its nightly stay in the House of the Underworld, whose door was in the west. In order to obtain an idea of the immense proportions ultimately assumed by these two diverging cults and the enormous influence they exerted upon the entire native civilization, it will be necessary to examine the form of the social organization in Montezuma’s time.