By these then, and other incidents, each of vast value, we may perceive how the primitive mind became gradually prepared for a change so imperatively necessary for all future progress, and how a habit even so deeply ingrafted as incest may primarily have been forced to slacken its hold. It is even possible to imagine how from such a point of departure, the custom might at once have entirely ceased among all, or at least a portion of, mankind. If we could conceive at this stage a secession from their original group of its resident component females, accompanied by their outside mates, with a continuance of the acceptance of the subordinate strange suitors in future generations of the new colony, then we could admit the probability of rapid evolution in approach to a well-known actual group formation. The persistent importation of the always dependent outsider would accentuate the movement already begun against incest--with two such associations in unison, cousinship would be recognised, and peaceful _connubium_ in ‘cross-cousin’ marriage between groups would become a habit, and female descent the rule.[4] But at such a stage in social evolution, it is impossible to accept the dominance of the unsupported female or ‘feme sole.’ _Gynæcocracy_, if it has indeed ever existed, is evidently as yet incredible. Not thus was dealt the final fatal blow at this last great trait of archaism. We must rather seek it in the familiar economy of the type of group we have left, which is characterised, as with other animals, by the predominance of the male. In our study of the various incidents in primitive social economy which would have had effect in a sense inimical to the custom of incest, we have only considered the matter from the point of view of the entry of the outside suitor after the death of the paternal tyrant. The incestuous rights of the living group-fathers are thereby in no way directly affected. In the absence of any direct personal interest in the matter on the part of the group-sons, the only other male components and law-makers might indeed continue to remain unopposed indefinitely. Thus a resolution of the problem of decay of incest would seem as far off as ever. Happily this is not in reality the case--the real significance of the entry of the outsider, even on such terms as we have examined, lay in the co-ordination of movement of these resultant primary checks, and the inevitable synchronous evolution of the most characteristic feature of the next and higher type of group, as in itself a mere component of a tribe. The outsider’s admission, in fact, really contained the germ of progress in group formation which was to entail the total required decay [of incest].