We have tried to portray the imperative evolution of a primal law as the sole possible condition of the first steps in social progress, a law which had so specially in view the bar to sexual intercourse between a brother and sister that it might, if a name for it were needed, be called the _anadelphogamous_ law. [Mr. Atkinson wrote ‘asororogamic,’ which is really too impossible a word for even science to employ.] Mr. Morgan, on the contrary, says,[1] ‘The primitive or consanguine family was founded upon the inter-marriage of brothers and sisters own and collateral in a group.’ He adds,[2] ‘The Malayan system defines the relationship that would exist in a consanguine family, and it demands the existence of such a family to account for its own existence.’ And again,[3] ‘It is impossible to explain the system as a natural growth, upon any other hypothesis than the one named, since this form of marriage alone can furnish a key to its interpretation.’ He bases his argument on the fact that[4] ‘under the Malayan system all consanguines, near and remote, fall within some one of the following relationships, viz. parent, child, grandparent, grandchild, brother and sister--no other blood relationships are recognised,’ and says, speaking of promiscuity, that[5] ‘a man calls his brother’s son, his son, because his brother’s wife is _his_ wife as well as his brother’s, and his sister’s son is also _his_ son because his sister is his wife.’ Now that a brother’s son should be called a son is quite simple, as being a natural effect of the group marriage of brothers, the prevalence of which as a habit, and its effects, MM. Lorimer and Fison so well show among the Australians.[6] But that a sister’s son should also be termed, by her brother, a ‘son’ is certainly a very different thing indeed, despite Mr. McLennan’s and other arguments to the contrary. In this verbal detail lies the whole crux of the matter as regards Mr. Morgan. That it should have given rise to such diversity of opinion and suggested his theory of brother and sister marriage need hardly be matter of surprise. For it is at once, evident that a group holding such nomenclature ignored cousinship, even if it existed. To all later seeming my sister’s son must be nephew to _ego_ quite necessarily. That at any stage he should be unrecognised as such seems the more astonishing, as even in the very early times when totems first arose, and arose probably and precisely to distinguish cousins as such,[7] each cousin is of a different totem to the other, and thus not only eligible in marriage with another cousin, but in many lower races the born spouse each of the other. The whole question thus resolves itself into the exact value of the term we find used in the Hawaiian designation of the sister’s son by her brother. Now it is important to note that two causes might have for effect the form of nomenclature in which a brother and sister each call the child a son, and thus ignore a possible cousinship.