1879.] NATURAL SCIENCES OF PHILADELPHIA. 61 



the Chimpanzee as it was that the cerebellum was relatively to 

 the cerebrum very much developed, Plate XII., Fig. 1. 



Of late years the convolutions of the human brain have been 

 very carefully described, and compared with those of the lower 

 animals; among others, by Bischorf, Ecker, Gratiolet, Pansch, 

 and Ilusche. And through the development of the theory, based 

 upon pathological, experimental, and comparative anatomical 

 facts, that, ceeteris paribus, the grade of the intelligence is propor- 

 tional to the number and complexities of the gyri and sulci, the 

 comparison of the brain of an anthropoid with that of Man be- 

 comes very interesting. So far as I know, the first distinct state- 

 ment that the convolutions are most numerous in the brain of 

 Man, and that his superior intelligence is due to this, is to be found 

 in the works of Eristratus, as quoted by Galen. In 1664 Willis 

 called attention to the lower animals having convolutions, though 

 fewer than Man, and that certain animals, like monkeys, had more 

 of them than carnivorous ones,'etc. Vicq. D'Azyr, in 1789, noticed 

 the want of symmetry in the convolutions in the brain of Man. 

 In 1794 Malacarne called especial attention to the convolution 

 known as the gyrus fornicatus. Tiedemann, in 1816, treated of the 

 development of the convolutions. While undoubtedly the anato- 

 mists just referred to may be said to have begun the study of the 

 convolutions, nevertheless it appears to me that the credit of a 

 sj'stematic study of the folds and fissures in a group of animals, 

 the comparison of such with those of Man, and the extension of 

 such investigation to the mammalia generally, belongs to Prof. 

 Richard Owen, who in 1833 distinguished in the Felidaa the folds 

 by letters and the fissures by figures, and what is more, named 

 them. In 1842 his views were much extended in the lectures de- 

 livered at the Royal College of Surgeons, when the homologous 

 convolutions were brought out strikingly in the diagrams by col- 

 ors. Leaving this little historical digression, and returning to 

 the brain of the Chimpanzee, I think it may be stated that in 

 most of the specimens examined so far all of the convolutions and 

 fissures described in the human brain can be identified. There is 

 no difficulty in recognizing the four lobes the frontal, parietal, 

 occipital, and temporal, Plate XL, Fig. 1 ; Plate XII., Fig. 1. The 

 central lobe or island of Red, which is very slightly convoluted, 

 is entirely concealed in the Chimpanzee. The frontal lobe exhi- 



