case, because the general motives to polyandry and polygyny persist and exercise a constant influence. Proof that this is the forgotten origin of group-marriage may perhaps be found in a remarkable feature of the customs of these tribes--one that is for the most part regarded as an inexplicable paradox. Marriage with the chief wife is not celebrated by ceremonies or festivals, as is the union with the secondary wife. Thus, the celebration occurs, not in connection with that marriage which is of primary importance even to the Australian, but, on the contrary, on the occasion of the union which is in itself of less importance. The solution of this riddle can lie only in the origin of the two forms of marriage. And, in fact, the two result from radically different causes, if it be true that capture from a friendly clan is the origin of the Tippamalku marriage and that assistance rendered to an allied companion underlies Pirrauru marriage. Capture is an act which precludes all ceremony; alliance with a companion is a contract, perhaps the very first marriage contract that was ever concluded--one that was made, not with the woman or with her parents, but with her husband. The consummation of such a contract, however, is an act which in early times was always accompanied by ceremonial performances. These accompanying phenomena may also, of course, persist long after their source has been lost to memory. Thus, the difference between the two forms of primitive group-marriage also indirectly confirms the supposition that monogamy lies at the basis of group-marriage in general. After a man has won one or more secondary wives in addition to his chief wife, in Pirrauru marriage, there will doubtless be a tendency for him to seek additional chief wives. This will be particularly apt to occur where, on the one hand, marriage by capture gives way to marriage by barter and later to marriage by purchase, and where, on the other hand, group-marriage is on the wane. Custom may then either recur to monogamy, or it may advance to a polygyny which is pure and not, as in the case of group-marriage, combined with polyandry. Whether the former or the latter will occur, will depend, now that marriage by purchase has become predominant, upon might and property. Since these are also the factors which insure man's supremacy within the family, the older forms of combined polyandry and polygyny almost universally (with few exceptions, conditioned by the dearth of women) give way, with the advance of culture, to simple polygyny, which is then practised alongside of monogamy. This polygyny, in turn, also finally recedes in favour of monogamy. The circle of development, accordingly, may be represented by the following diagram:-- Monogamy | Polyandry | Polyandry with Polygyny (Group-marriage) | Polygyny | Monogamy.