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Show 1905.] BRAIN OF THE BLACK APE. 25 Baboon, it is nevertheless important to point it out, particularly so in view of the second brain, which may or may not invalidate the general applicability of the above statement as to the brain of Cynopithecus. The question of course as to the second brain is, whether its differences are variations in an adult brain or are due to youth or sex, or both. This smaller ape only lived for six months in the Society's Gardens, and as there is no further evidence as to its age, it is impossible to be certain upon the point. I am disposed, however, to think that this small brain is comparatively undeveloped, and the differences which it shows from the larger brain would have lessened with age. Text-fig. 12. a. Inferior occipital fissure; P . Parallel fissure. Other lettering as in text-fig. 11. These differences, it will be observed, can be mostly explained on that view. The simple calcarine fissure is simply minus the top bar of the T, which will ultimately appear; the Sylvian fissure has not yet grown sufficiently far back to meet the parallel fissure; the lower portion of the inferior temporal sulcus is undeveloped ; a further growth forward of the operculum would alter the bending of the intraparietal fissure and perhaps shift forward the direction of the internal parieto-occipital. In fact, all the peculiarities of the smaller Cynopithecus brain may conceivably be explained on this view. If this be correct, we can draw the interesting inference that the Semnopithecine brain is relatively to the Macacine at a lower level. If, on the other hand, the differences between the two brains are variations of completely adult structure, it is no longer |