lobus anterior paullulum acuminatus; b, lobus medius; c, lobus posterior, "cerebellum obtegens." Fig. 2, represents the brain of "Simia rhesus;" and the explanation of the figures says: "a, lobus anterior; b, lobus medius; c, lobus posterior." Fig. 3, a figure of the brain of Simia sabœa, and fig. 4, of "Simia capucina" have the same lettering, and the letters have the same signification.
And, to permit of no mistake, Tiedemann, at page 48 of the same work, tells us expressly:—
"Cerebrum simiarum quoad magnitudinem et divisionem in lobos ad humanum proxime accedit: dividitur enim per fissuram mediam longitudinalem in duo æqualia hemisphœria quorum utrumque rursus in tres lobos partitur. Lobi posteriores uti in homine faciem superiorem cerebelli obtegunt. In cæteris a nobis dissectis quodrupedibus encephali hemisphæria sunt magis plana et brevia. Lobi posteriores quamvis breviores quam in Simiis tantommodo in Phoca occurrunt, in reliquis Feris in Leone, Fele, Nasua, Lotore, et ipso Lemure ac Bradypode cerebellum fere nudum vel ab hemisphæriis haud obtectum conspicitnr."
In 1825, Tiedemann, describing the brain of the orang (Hirn des Orangs mit dem des Menschen verglichen), particularly states that each hemisphere is, as in man, divided into three lobes—an anterior, a middle, and a posterior; and that the ovate cerebral hemispheres cover the cerebellum almost entirely, though they do not, as in man, project beyond its posterior margin.
In the third volume of the second edition of the "Leçons," Cuvier expressly affirms, in speaking of the apes:—
"Their hemispheres are also prolonged back wards, "as in man, to form the posterior lobes, which repose on the cerebellum.
"The cerebellum is almost wholly covered by the hemispheres in the seal and otter.
"In the dolphin, a large proportion of the cerebellum is covered."—pp. 84–86.
And, in the "Regne Animal," he gives as part of the definition of the order Quadrumana: "Le cerveau a trois lobes de chaque côté, dont le postérieur recouvre le cervelet."
In his elaborate essay "On the brain of the negro, compared with that of the European and the orang outang," published in the Philosopical Transactions for 1838, Tiedemann's zeal for the cause of the oppressed black has occasionally led him into something very like special pleading; and yet he does not dream of hinting the absence of the posterior, or third lobe, present in the negro's brain, from that of the orang. His summary, at p. 518, runs thus:—
"The brain of the monkey and the orang outang differs, as follows, from the human brain:—
"1. The brain is absolutely and relatively smaller and lighter, shorter, narrower, and lower than the human brain.
"2. The brain is smaller, in comparison to the size of the nerves, than in man.
"3. The hemispheres of the brain are, relatively to the spinal marrow, medulla oblongata, the cerebellum, corpora quadrigemina, the thalami optici, and corpora striata, smaller than in man.
"4. The gyri and sulci of the brain are not so numerous as in man."
