Unless external influences have changed his mode of life, primitive man, as we have seen, is both monogamous and endogamous, the latter term being used in a relative sense as denoting a condition in which marriages are permitted between blood relations as well as between non-relations. As a result of the external conditions of life, however, particularly the common habitation of the same protective cave and the use of adjacent hunting-grounds, unions within a wider joint family generally predominate. Following upon the rise of exogamy, polygamy also regularly appears. These two practices give to the marriage and family relations of totemic society an essentially different character from that which they possess under primitive conditions. Even in the totemic era, indeed, polygamy is not universal; monogamy continues to survive. Monogamy, however, ceases to be a norm of custom. It is everywhere set aside, to a greater or less extent, in favour of the two forms of polygamy--polygyny and polyandry. Now it is apparent that precisely the same conditions that underlie the development of the various forms of exogamy also generate _polygyny_ and _polyandry_. From the standpoint of the general human impulses determining the relations of the sexes, both sorts of polygamy are manifestly connected very closely with the origin of exogamy. Here, again, the fact that exogamy originated in marriage by capture from within the tribe is of decisive importance. It is precisely this friendly form of the capture of brides, as we may learn from the example of the Australians and of others, that is never carried out by the individual alone, whether the custom be still seriously practised or exists only in playful survivals. The companions of the captor aid him, and he, in turn, reciprocates in similar undertakings. Thereby the companion, according to a view that long continued to be held, gains a joint right to the captured woman. Hence the original form of polygamy was probably not polygyny--the only form, practically, that later occurs--but _polyandry_. At first this polyandry, which originates in capture, was probably only temporary in character. Nevertheless it inevitably led to a loosening of the marriage bond, the result of which might easily be the introduction of polygyny. The man who has gained a wife for his permanent possession seeks to indemnify himself, so far as possible, for the partial loss which he suffers through his companions. Here, then, two motives co-operate to introduce the so-called 'group-marriage'--the dearth of women, which may also act as a secondary motive in the claim of the companions to the captured woman, and the impulse for sexual satisfaction, which is, in turn, intensified by the lack of women. Similarly, the right to the possession of a woman, even though only temporarily, also has two sources. In the first place, the helper demands a reward for his assistance. This reward,