Page:Geological Evidences of the Antiquity of Man.djvu/508

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STRUCTURE OF BRAIN
CHAP. XXIV.

Ateles (Spider Monkey).

Cebus (Capuchin Monkey).

Pithecia (Saki).

Nyctipithecus (Douricouli).

Hapale (Marmoset).

Otolicnus.

Stenops.

Lemur.


In July, 1861, Mr. Marshall, in a paper on the brain of a young Chimpanzee, which he had dissected immediately after its death, gave a series of photographic drawings, showing that when the parts are all in a fresh state, the posterior lobe of the cerebrum, instead of simply covering the cerebellum, is prolonged backwards beyond it even to a greater extent than in Gratiolet's figure, 56, p. 482, and, what is more in point, in a greater degree relatively speaking (at least in the young state of the animal) than in Man. In fact, 'the projection is to the extent of about one-ninth of the total length of the cerebrum, whereas the average excess of overlapping is only one-eleventh in the human brain.'[1]

The same author gives an instructive account of the manner in which displacement and distortion take place when such brains are preserved in spirits as in the ordinary preparations of the anatomist.

Mr. Flower, in a recent paper on the posterior lobe of the cerebrum in the Quadrumana,[2] remarks, that although Tiedemann had declared himself unable in 1821 to detect the hippocampus minor or the posterior cornu of the lateral ventricle in the brain of a Macacus dissected by him, Cuvier, nevertheless, mentions the latter as characteristic of Man and the apes, and M. Serres, in his well-known work on the brain in 1826, has shown in at least four species of apes

  1. Natural History Review, July 1861, by John Marshall, F.R.S., Surgeon to University College Hospital. See also on this subject Professor Rolleston on the slight degree of backward extension of the cerebrum in some races of Man. Medical Times, October 1862, p. 419.
  2. Philosophical Transactions, 1862, p. 185.