We have seen above how to the phases of the new and the full moon that of the waning moon is added as a third. When the gradual development of the moon is regarded--as is done when numbers are used--and not the particular shape of it appearing on a certain day, we also get three periods, since between the waxing and the waning occurs the full moon, and this, although not in the strictest sense, lasts longer than a day, and unlike the waxing and the waning moon remains in the sky the whole night long. The time of full moon therefore appears as a third independent period between the waxing and the waning. The impulse to a tripartite division hereby given clashed with the decimal system of enumeration of most peoples; as a rule the counting was suspended at the basal series of numbers. In this manner we may account for the not uncommon phenomenon that only ten months are numbered, the two others being called by special names[707]. Thus arises the division of the month into three decades, in which however the last decade may vary between 9 and 10 days. The division into decades is not so common as the halving of the month. The Zuñi of Arizona divide the month into three decades, each of which is called a ‘ten’[708]. The Ahanta of the western Gold Coast divide the moon-month into three periods, two of ten days each, the third--which lasts until the new moon appears--of about 9½ days (more correctly, no doubt, varying between 9 and 10 days). The Sofalese of East Africa must have done the same, since de Faria says that they divided the month into 3 decades and that the first day of the first decade was the feast of the new moon[709]. The Masai, who number either the days of the whole month consecutively or the days of its two halves, nevertheless give special prominence to the initial days of the decades (alongside of other notable days), and call them _negera_[710]. Among the Greeks the division into decades displaced the older bisection. Of the names of the decades the first and third refer to the concrete form of the moon: μὴν ἱστάμενος, older ἀεξόμενος[711], literally ‘the appearing, waxing moon’, and μὴν φθίνων, ‘the waning moon’. For originally μήν must here have had the sense of ‘moon’ which the etymology suggests. The second decade was called μὴν μεσῶν, ‘the month at the middle’: the epithet shews that μήν here means ‘month’, and not ‘moon’. This name is therefore younger than the two others, which must once have been used to describe the two halves of the month, and do so still in Homer[712].