The Latin word gens, used by Morgan generally for the designation of this sex organization, is derived, like the equivalent Greek word genos, from the common Aryan root gan, signifying to beget. Gens, genos, Sanskrit dschanas, Gothic kuni, ancient Norse and Anglesaxon kyn, English kin, Middle High German künne, all signify lineage, descent. Gens in Latin, genos in Greek, specially designate that sex organization which boasted of common descent (from a common sire) and was united into a separate community by certain social and religious institutions, but the origin and nature of which nevertheless remained obscure to all our historians.

Elsewhere, in speaking of the Punaluan family, we saw how the gens was constituted in its original form. It consisted of all individuals who by means of the Punaluan marriage and in conformity with the conceptions necessarily arising in it made up the recognized offspring of a certain ancestral mother, the founder of that gens. Since fatherhood is uncertain in this form of the family, female lineage is alone valid. And as brothers must not marry their sisters, but only women of foreign descent, the children bred from these foreign women do not belong to the gens, according to maternal law. Hence only the offspring of the daughters of every generation remain in the same sex organization. The descendants of the sons are transferred to the gentes of the new mothers. What becomes of this group of kinship when it constitutes itself a separate group, distinct from similar groups in the same tribe?

As the classical form of this original gens Morgan selects that of the Iroquois, more especially that of the Seneca tribe. This tribe has eight gentes named after animals: 1. Wolf. 2. Bear. 3. Turtle. 4. Beaver. 5. Deer. 6. Snipe. 7. Heron. 8. Hawk. Every gens observes the following customs:

1. The gens elects its sachem (official head during peace) and its chief (leader in war). The sachem must be selected within the gens and his office was in a sense hereditary. It had to be filled immediately after a vacancy occurred. The chief could be selected outside of the gens, and his office could even be temporarily vacant. The son never followed his father in the office of sachem, because the Iroquois observed maternal law, in consequence of which the son belonged to another gens. But the brother or the son of a sister was often elected as a successor. Men and women both voted in elections. The election, however, had to be confirmed by the other seven gentes, and then only the sachem-elect was solemnly invested, by the common council of the whole Iroquois federation. The significance of this will be seen later. The power of the sachem within the tribe was of a paternal, purely moral nature. He had no means of coercion at his command. He was besides by virtue of his office a member of the tribal council of the Senecas and of the federal council of the whole Iroquois nation. The Chief had the right to command only in times of war.

2. The gens can retire the sachem and the chief at will. This again is done by men and women jointly. The retired men are considered simple warriors and private persons like all others. The tribal council, by the way, can also retire the sachems, even against the will of the tribe.

3. No member is permitted to marry within the gens. This is the fundamental rule of the gens, the tie that holds it together. It is the negative expression of the very positive blood relationship, by virtue of which the individuals belonging to it become a gens. By the discovery of this simple fact Morgan for the first time revealed the nature of the gens. How little the gens had been understood before him is proven by former reports on savages and barbarians, in which the different organizations of which the gentile order is composed are jumbled together without understanding and distinction as tribe, clan, thum, etc. Sometimes it is stated that intermarrying within these organizations is forbidden. This gave rise to the hopeless confusion, in which McLennan could pose as Napoleon and establish order by the decree: All tribes are divided into those that forbid intermarrying (exogamous) and those that permit it (endogamous). And after he had thus made confusion worse confounded, he could indulge in deep meditations which of his two preposterous classes was the older: exogamy or endogamy. By the discovery of the gens founded on affinity of blood and the resulting impossibility of its members to intermarry, this nonsense found a natural end. It is self understood that the marriage interdict within the gens was strictly observed at the stage in which we find the Iroquois.

4. The property of deceased members fell to the share of the other gentiles; it had to remain in the gens. In view of the insignificance of the objects an Iroquois could leave behind, the nearest gentile relations divided the heritage. Was the deceased a man, then his natural brothers, sisters and the brothers of the mother shared in his property. Was it a woman, then her children and natural sisters shared, but not her brothers. For this reason husband and wife could not inherit from one another, nor the children from the father.

5. The gentile members owed to each other help, protection and especially assistance in revenging injury inflicted by strangers. The individual relied for his protection on the gens and could be assured of it. Whoever injured the individual, injured the whole gens. From this blood kinship arose the obligation to blood revenge that was unconditionally recognized by the Iroquois. If a stranger killed a gentile member, the whole gens of the slain man was pledged to revenge his death. First mediation was tried. The gens of the slayer deliberated and offered to the gentile council of the slain propositions for atonement, consisting generally in expressions of regret and presents of considerable value. If these were accepted, the matter was settled. In the opposite case the injured gens appointed one or more avengers who were obliged to pursue the slayer and to kill him. If they succeeded, the gens of the slayer had no right to complain. The account was squared.

6. The gens had certain distinct names or series of names, which no other gens in the whole tribe could use, so that the name of the individual indicated to what gens he belonged. A gentile name at the same time bestowed gentile rights.

7. The gens may adopt strangers who thereby are adopted into the whole tribe. The prisoners of war who were not killed became by adoption into a gens tribal members of the Senecas and thus received full gentile and tribal rights. The adoption took place on the motion of some gentile members, of men who accepted the stranger as a brother or sister, of women who accepted him as a child. The solemn introduction into the gens was necessary to confirm the adoption. Frequently certain gentes that had shrunk exceptionally were thus strengthened by mass adoptions from another gens with the consent of the latter. Among the Iroquois the solemn introduction into the gens took place in a public meeting of the tribal council, whereby it actually became a religious ceremony.