The classification and account of the Pueblo phratries and gentes form an important contribution to anthropology, and the discussion upon the origin and use of the kivas is more explanatory and exhaustive than any before made on that subject. This word of the Tusayan language is adopted to take the place of the Spanish term “estufa,” which literally means a stove, and is misleading, because it strictly applies only to the sweat houses which lodge-building Indians use. The kiva is the ceremonial chamber of the ancient and modern Pueblo peoples. They are found wherever the remains of Pueblo architecture occur, and are distinguished from the typical dwelling rooms by their size and position and generally by their form. The author dwells instructively upon the antiquity, excavation, access, exterior masonry, orientation, and general construction, furniture, and ornaments of these remarkable chambers, and upon the rites connected with them. He also gives an original and acute suggestion to account for the persistence of the structural plan of the kivas by its religious or mythologic signification. The designation of the curious orifice of the sipapuh as “the place from which the people emerged,” in connection with the peculiar arrangement of the kiva interior with its change of floor level, suggested to Mr. Mindeleff that these features might be regarded as typifying the four worlds of the genesis myth that has exercised such an influence on Tusayan customs. He was also led to infer that it typifies the “four houses” or stages described in their creation myths. The sipapuh, with its cavity beneath the floor, is certainly regarded as indicating the place of beginning, the lowest house under the earth, the abode of Myuingwa, the Creator; the main or lower floor represents the second stage; and the elevated section of the floor is made to denote the third stage, where animals were created. At the New Year festivals animal fetiches were set in groups upon this platform. It is also to be noted that the ladder to the surface is invariably made of pine, and always rests upon the platform, never upon the lower floor, and in their traditional genesis it is stated that the people climbed up from the third house (stage) by a ladder of pine, and through such an opening as the kiva hatchway. The outer air is the fourth world, or that now occupied.