all Polynesia, compels us to acknowledge its former existence, for it exhibits grades of kinship that could only originate in this form of the family. And the whole subsequent development of the family compels us to admit this form as a necessary step.
2. THE PUNALUAN FAMILY.
While the first step of organization consisted in excluding parents and children from mutual sexual intercourse, the second was the erection of a barrier between brother and sister. This progress was much more important on account of the greater equality in the ages of the parties concerned, but also far more difficult. It was accomplished gradually, probably beginning with the exclusion of the natural sister (i.e., on the mother's side) from sexual intercourse, first in single cases, then becoming more and more the rule (in Hawaii exceptions were still noted during the nineteenth century), and finally ending with the prohibition of marriage even among collateral brothers and sisters, i.e., what we now term brother's and sister’s children, grandchildren, and great-grandchildren. This progress offers, according to Morgan, an excellent illustration how the principle of natural selection works. Without question, the tribes limiting inbreeding by this progress developed faster and more completely than those retaining the marriage between brothers and sisters as a rule and law. And how powerfully the influence of this progress was felt, is shown by the institution of the gens, directly attributable to it and passing far beyond the goal. The gens is the foundation of the social order of most, if not all, barbarian nations, and in Greece and Rome we step immediately from it to civilization.
Every primeval family necessarily had to divide after a few generations. The originally communistic
