Darwin made easy / by Edward B. Aveling.

  • Edward Aveling
Date:
1893
Catalogue details

Licence: Public Domain Mark

Credit: Darwin made easy / by Edward B. Aveling. Source: Wellcome Collection.

    151/156 page 47
    4 T though present, is deeply placed in the fissure, not super- ficial and visible on the exterior. In the Gorilla the first or upper is present, but is deeply placed, not superficial, and apparently the second is absent. The Orang has the first, and, unlike all the other anthrop- oid apes, has this upper annectent convolution superficial and visible at once to the eye. The second is, however, absent. Man has generally both the upper and the lower on each side, and both are superficial. But neither is quite a con- stant in the human brain, and in the Orang the first or upper, resembling, as it does that of man in its superficial position, resembles it also in its variability. Indeed, it is of these convolutions Rolleston wrote the words quoted on p. 44. Now lastly, as to the supra-marginal lobule. This, as \ have said above (p. 36), was regarded as the crucial anatomi- cal point of distinction between Man and his fellows. Man had the supra-marginal lobule and no other Primate had. Thus Gratiolet. Let us once more recall the exact position of this cerebral structure. It lies at the top of the Sylvian fissure folding over this from before backwards. All the three highest anthropoids have in their brains this convolu- tion. It does not really appear until the Chimpanzee. In the brain of this ape the supra-marginal lobule is, at the best, only rudimentary. In the Orang it is more fully developed, and in the Gorilla brains that have been thus far examined, this convolution, supposed by Gratiolet to be the special prerogative of Man, is found to be existent in a yet more notable degree. With these discoveries vanishes the last imaginary distinction between the human and Simian brain. In its train vanishes the whole dream-series of anatomical prerogatives of Man and the very idea that he is a special creation.
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