Among the tribes of Guiana, according to Mr. Im Thurn, marriage is now almost always, as formerly it was always, contracted between members of different families, and, descent being traced through females, no intermarriage with relations on the mother’s side is permitted.[1762] The Mundrucûs are divided into clans, the members of which are strictly prohibited from forming alliances with others of the same clan. “A Mundrucû Indian,” says Professor Agassiz, “treats a woman of the same order (clan) with himself as a sister, any nearer relation between them is impossible.”[1763] The Indians of Peru are restricted from marriage within the first four degrees.[1764] The Guaranies and Abipones abhor alliances with even the remotest relations.[1765] And as to the Yahgans of Tierra del Fuego, Mr. Bridges writes to me that “no marriage, no intercourse ever takes place among blood-relations even to second cousins.” Such intercourse is held in utter abomination and is never heard of. Also between half-brothers and half-sisters marriages do not occur. Nowhere is marriage bound by more severe laws than among the Australian aborigines. Their tribes are, as a rule—and probably as a rule without exceptions[1766]—grouped in exogamous subdivisions, the number of which varies considerably. There are tribes in which members of any clan are free to marry members of any clan but their own; but such tribes are exceptional.[1767] “Often,” says Mr. Frazer, “an Australian tribe is divided into two (exogamous) phratries, each of which includes under it a number of totem clans; and oftener still there are sub-phratries interposed between the phratry and the clans, each phratry including two sub-phratries, and the sub-phratries including totem clans.”[1768] Most of Mr. Curr’s very numerous correspondents who have touched on this question have, however, given the number of subdivisions in their neighbourhood as four only.[1769] Before the occupation of the country by the whites, which quickly breaks down aboriginal customs, any departure from the marriage system founded on this division was looked on with absolute horror, and even spoken of with reluctance. Indeed, when marriage or sexual intercourse with a person of a forbidden clan did occur, the regular penalty inflicted on the parties implicated was death.[1770] And it is a noteworthy fact, generally overlooked by anthropologists, that besides these prohibitions arising from the clan-system and, naturally, applying only to the father’s or, more generally, only to the mother’s relations, there is, as it seems everywhere, a law which forbids the marriage of persons near of kin.[1771] “A man,” says Mr. Curr, “may not marry his mother, sister, half-sister, daughter, granddaughter, aunt, niece, first or second cousin.”[1772] Among the Kurnai of Gippsland, according to Mr. Bulmer, even third cousins are within the prohibited degrees of relationship.[1773] Moreover, certain tribes, besides having the