It may be approached first from the conjectural basis. On this basis it may be asserted that the victorious male of the primary groups would remain victorious only just so long as he could continue to adjust the conditions on the primary basis, and preserve his females to himself. New conditions would arise whenever the limitation of the food lands produced a degree of localisation of the hitherto movable groups. There would then have crept into human experience the necessity for something of common action among a wider range than the simple group. This is a new force, and social evolution is henceforth going to operate in addition to, perhaps to a limited extent in substitution of, the constant movement towards new food lands. The single male would no longer be the victorious male by himself; and sharing his power with other males meant the reduction of his power in his own group. Called away for something more than the defence of his own primary group of females, he would leave the females with the practical governance of the primary groups. This tendency would develop. Wherever the constant movement outwards became stayed by geographical or other influences, the groups which experienced the shock of stoppage would undergo change. The female in the various primary groups would become a static element, and the male alone would follow out in the more restricted area the older force of movement which he had learned during the period of unrestricted scope.[355] He would have to find his mates during his roamings, instead of the former condition of fighting for them during the group movements; and his relationship to the primary groups would be therefore fundamentally changed. From being the central dominant head, he would become a constantly shifting unit. The female under these conditions would become the centre of the new social unit, and the male would become the hunter for food and the fighter against enemies. The new social forces would thus consist of local units commanded by the female, and revolving units composed of the males, and there would arise therefrom cleavage between the economic conditions of the two sexes. That primitive economics bear the impress of sex cleavage is borne out by every class of evidence, and it is in this circumstance that we first come upon societies distinguished by containing two of the most important social elements, exogamy and totemism. Before, however, examining examples of societies containing the two elements of exogamy and totemism, it will be necessary to say something by way of preliminaries on these two elements themselves. They have rightly been made the subject of important special inquiry by anthropological scholars, as being in fact the key to the question of social evolution, and we shall clear the ground considerably by first of all turning to the principal authorities on the subject, and ascertaining the present position of the inquiry.