Here then we find renewed, in act of custom, another bar to intercourse between certain individuals of different sexes. And not only as a peace-conferring covenant would the fresh step in progress be important. It marks another stride in advance from brute to man, in the further recognition of points of difference between one female and another from a sexual point of view, the genetic evolution of which sentiment, in the primal law, foreshadowed such latent potentiality as already distinctive of mankind alone. Social advance to this stage has entailed the genesis of law in definition of respective marital rights as _between the two generations_, viz. fathers and sons, but further evolution in regulation of the individual right, as within the generation itself, is evidently indicated. For all members of the latter, as is the case to-day with many lower people, would be considered, _de facto_, a _class_, in which all are regarded as brothers, own or tribal, whose interest in all things regarding their classificatory rights would be in common.[3] Such would be more especially the case in respect to female captives, whose capture would be the act of all. Here sexual jealousy, if uncontrolled, would inevitably lead to repetitions of that violent segregation of the members which occurred under the same circumstances amidst their primitive prototypes--i.e. that band of isolated young males, contemporaries of and exiles from some Cyclopean family. We may, however, surmise that, now or soon, the general development of intelligence and advance in social feeling would permit the action of the necessary rule in remedy. That rule would doubtless take the form we still find existing to-day for regulation in parallel circumstances, a rule which simply accords priority of right in accordance with seniority in birth. Such right would in itself accrue naturally as with other animals, from the fact that superior strength is found with greater age. This prior possession is not incompatible with an amicable recognition of the privilege of later participation by others. If such recognition took place in favour of the rights of the juniors, whilst they again peacefully accepted the larger pretensions of the seniors within their class, then natural selection would again act in their favour by the elimination of groups unable to abide such conditions. The arrogation of sole possession could but lead to the disintegration of the troop.[4] Another solution of the problem of rights as between brothers may here be noted: it is that which is common to such widely separated spots as New Caledonia and Orissa, viz. the law of avoidance between an elder brother and a younger brother’s wife. It is one of the most strict and severe. It is, however, incompatible with group marriage, which we are now dealing with.[5] It marks the genetic stage of monandry.