The brain of a black monkey, Macacus maurus: The relative prominence of different gyri

Harris E. Santee
1914 The Anatomical Record  
This brain measures 7 em. from frontal to occipital pole. Its greatest transverse measurement is 6.2 em. ; and 4.5 em. is the height of a cerebral hemisphere. The entire weight equals 114.95 grams, of which the cerebrum comprises 103.29 grams and the rhombencephalon 11.66 grams. The measurements are approximately proportional to the corresponding dimensions of the human brain; but the relative weight of the cerebrum is nine-tenths of the whole brain. In man the cerebrum constitutes seven-eights
more » ... of the brain. Upon examining this brain, one familiar with the human brain is impressed with the probable significance of three facts, namely, a remarkable shortening of the frontal region, an abundant fullness of the occipital and hippocampal regions, and a marked prominence of the central gyri. The central sulcus of Rolando is far from central in position; it divides the convex surface, above and behind the lateral fissure of Sylvius, very nearly into an anterior third and a posterior two-thirds, a notable variation from the proportions of the human brain. These variations from the human proportions should be in perfect harmony with the widely different psychic functions performed by the brains of man and monkey. Moreover, the high development of the motor and sensory nerves of the monkey and their very strong resemblance to the peripheral nervous 257
doi:10.1002/ar.1090080504 fatcat:ermr46blpvaubihmyo26otfuxa