The author has relied to a large extent on the well-known works cited in the bibliography at the end, but it is only fair to the reader to mention the fact that many of the statements are founded on unpublished researches made by the author. The last chapter sums up the story of man's origin, and the reader, especially if unfamiliar with the geological divisions of time, may find it profitable to refer to this chapter when the first two or three have been read.

A. Keith,

Royal College of Surgeons of England, London, W.C.