I Have endeavoured to show, in the preceding Essay, that the Anthropini, or Man Family, form a very well defined group of the Primates, between which and the immediately following Family, the Catarhini, there is, in the existing world, the same entire absence of any transitional form or connecting link, as between the Catarhini and Platyrhini.

It is a commonly received doctrine, however, that the structural intervals between the various, existing modifications of organic beings may be diminished, or even obliterated, if we take into account the long and varied succession of animals and plants which have preceded these now living and which are known to us only by their fossilized remains. How far this doctrine is well based, how far, on the other hand, as our knowledge at present stands, it is an overstatement of the real facts of the case, and an exaggeration of the conclusions fairly deducible from them, are points of grave importance, but into the discussion of which I do not, at present, propose to enter. It is enough that such a view of the relations of extinct to living beings has been propounded, to lead us to inquire, with anxiety, how far the recent discoveries of human remains in a fossil state bear out, or oppose, that view.