The details of the anatomical argument, which Darwin said would undoubtedly lead the naturalist to classify Negro and European as distinct species, are matters of readily accessible knowledge. They have been presented frequently and with telling force. That in particular the cranial, the facial, and the appendicular skeletons of the dolichocephalic West African (the purest, the lowest, and the prevalent type on the plantation) deviate sensibly from the highest human towards the quadrumanal stamp, has been the common observation of naturalists from Blumenbach to Ratzel; nor can this have escaped the notice of intelligent and unbiased laymen. Nevertheless, it may be well to record the authoritative statement made by A. H. Keane, professor of Hindustani, University College, London, in the article "Negro," in the Encyclopædia Britannica, Vol. XVII.[10] [10] For a fuller statement of some particulars, see Chapter Four. "But wherever found in a comparatively pure state, as on the coast of Guinea (here apparently is to be met the most pronounced Negro type proper yet discovered), in the Gaboon, along the lower Zambesi, and in the Benua and Shari basins, the African aborigines present almost a greater uniformity of physical and moral type than any of the other great divisions of mankind. By the nearly unanimous consent of anthropologists this type occupies at the same time the lowest position in the evolutionary scale, thus affording the best material for the comparative study of the highest anthropoids and the human species. The chief points in which the Negro either approaches the _Quadrumana_ or differs most from his congeners are: (1) The abnormal length of the arm, which in the erect position sometimes reaches the knee-pan, and which on an average exceeds that of the Caucasian by about 2 inches. (2) Prognathism, or projection of the jaws (index number of facial angle about 70, as compared with the Caucasian 82). (3) Weight of brain, as indicating cranial capacity, 35 ounces (highest gorilla 20, average European 45). (4) Full black eye, with black iris and yellowish sclerotic coat, a very marked feature. (5) Short flat snub nose, deeply depressed at the base or frontal suture, broad at extremity, with dilated nostrils and concave ridge. (6) Thick protruding lips, plainly showing the inner red surface. (7) Very large zygomatic arches--high and prominent cheek bones. (8) Exceedingly thick cranium, enabling the Negro to butt with the head and resist blows which would inevitably break any ordinary European's skull. (9) Correspondingly weak lower limbs, terminating in a broad flat foot with low instep, divergent and somewhat prehensile great toe, and heel projecting backwards ("lark heel").