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Rh slowly effaced with age, and in the adult it has completely disappeared. The brain of the Hottentot Venus is, then, in all respects, inferior to that of white men arrived at the normal term of their development. It can be compared only with the brain of a white who is idiotic from an arrest of cerebral development."—p. 66.

Finally, with respect to the fourth difference, Tiedemann observes (p. 515) of the negro's brain:—

Thus, the cerebral hemispheres of the Bosjesman (and to a certain extent of the negro), so far as the evidence before us goes, are different from those of the white man; and the circumstances in which they differ—viz., the more pointed shape of the cerebral hemispheres, the greater symmetry of their convolutions, and the different development of certain of these convolutions,—are all of the same nature as most of those which distinguish the ape's brain from that of man. In other words, if we place A, the European brain, B, the Bosjesman brain, and C, the orang brain, in a series, the differences between A and B, so far as they have been ascertained, are of the same nature as the chief of those between B and C.

The brains of the lowest races of mankind have been hardly at all examined; and it would be a matter of great interest to ascertain whether, in these races, there is any trace of the external perpendicular fissure, any diminution of the lobule of the marginal convolution, and any increase of the proportional size of the nerves to the cerebral mass. Medical men living at the Cape of Good Hope, in Australia, and within reach of the Hill-men of India, will, it is to be hoped, some day solve these problems for the zoologist.

Let it be admitted, however, that the brain of man is absolutely distinguished from that of the highest known apes—

1st. By its large size, as compared with the cerebral nerves;

2nd. By the existence of the lobule of the marginal convolution;

3rd. By the absence of the external perpendicular fissure—And then let us turn to the other side of the argument, and weigh these differences against those which separate the brains of Pithecus or Troglodytes from those of the lowest Quadrumana.

The brain of Lemur mongos is well figured, and constantly referred to by Tiedemann in the "Icones" so often referred to. The few gyri; the shortness of the cerebral hemispheres, in the region of the third lobe, which leave fully half the cerebellum uncovered; the large size of the vermis superior; the prominence of its flocculus; the great size of the olfactory nerves, which rather deserve the name of olfactory lobes; the singleness of the corpora candicantia; the comparatively small and flat pons varolii; the presence of corpora trapezoidea; and, in