There is a considerable amount of evidence to show that exogamy, where now in force, was preceded by a period in which the unions prohibited under its rule were freely indulged in, though the marriage tie was at the same time broader and less binding. Thus of the Central Australians Spencer and Gillen[231] say that tradition "seems to point back to a time when a man always married a woman of his own totem. The reference to men and woman of one totem always living together in groups would appear to be too frequent to admit of any other satisfactory explanation. We never meet in tradition with an instance of a man living with a woman who was not of his own totem." The same conclusion as to the former universal prevalence of endogamy emerges from a study of the actually observed condition of the Australian natives, the rude and uncultivated tribes of the interior being still to some extent endogamic, while there is a gradual increase in the frequency and strictness of exogamy, as we proceed from these to the more advanced communities of the north[232]. Among the Kacharis of Assam we have an example of what is probably the still more primitive process of a _compulsory_ endogamy giving place to freedom to marry outside the totem group, endogamy being here thus not only permitted but enjoined[233]. Other indications of the co-existence of endogamy with a totemic system are found in Madagascar[234] and in N.W. America[235]. [Sidenote: Really primitive races mostly monogamous and endogamous] Frazer supposes that exogamy in its beginning arose originally as a restriction upon complete promiscuity, though he admits that such promiscuity need not have been characteristic of absolutely primitive man[236]. As a matter of fact the most primitive races that we know seem to be usually _monogamous_ and _endogamous_. This is for instance to a greater or less extent the case with the Veddahs[237], the Andamanese[238], the lowest forest tribes of Brazil[239], the inhabitants of the interior of Borneo[240], the Semangs and Senoi of the Malay Peninsula[241], and the Negritos of the Philippines[242] and Central Africa[243]. [Sidenote: The family is therefore their principal social unit] [Sidenote: Incest a natural consequence of such conditions]