As the criticism respecting the _general_ characteristics, has its bearing upon the relations of the American aborigines to those of the world at large, so that of the _sectional_ ones determines our views as to their unity or non-unity among themselves. It is the same in both cases. It is an easy matter to say that the Athabaskans (for instance) burn their dead to ashes, whilst the Peruvians desiccate them into mummies; that the Nehannis treat their women with respect, whilst servitude, on the part of the female, is the rule elsewhere; or that (enterprise and industry being exceptional phænomena in the western hemisphere), the Waraws are navigators, and the Haidah islanders tradesmen; and easier still is it to discover that in populations which live on fishing, we miss certain elements of the social state of the hunter or agriculturist. The real difficulty is to take the exact measure of their value. Failing the _data_ for doing this, the parallel statement of the points of agreement becomes a duty on the part of the ethnologist. Now, in this respect, the phenomenon which has been noticed in Australia, reappears in America, viz.: a habit or custom, which shall not be found in more than one or two tribes in the neighbourhood of each other, shall appear, as if wholly independent of mutual imitation, at some other (perhaps some distant) part of the island. Such, in Australia, was the case of similar family names; and such in America is the remarkable distribution of the habits of flattening the head, and burying on elevated platforms; to say nothing of the two parallel forms of semicivilization in Mexico and Peru, so concordant on the whole, yet differing in so many details, and, evidently, separate and independent developments rather than the results of an extension of either one or the other as the original. The same reasons which prevent us, in the present state of our knowledge, from drawing any inferences into the higher problems of ethnology from those manners and customs of the American Indians, which in the mere way of simple description give so much interest to the writings of the adventurous traveller, save us the necessity of exhibiting them in detail. No such economy, however, of time and paper is allowed in respect to a question which has already been more than once alluded to, viz.: the peculiarities of the American languages; peculiarities which are as remarkable in respect to the points wherein they agree, as they are in respect to the points wherein they differ--peculiarities, however, which, remarkable as they are, may easily be over-rated.