AND AFFINITIES OF THE GORILLA. 253 
Monkeys are more anthropoid than it; they have a proportionally larger and more 
human-shaped cranium, much less prominent jaws, with more equable teeth. 
In the skeletons of the adult males of the Gorilla, Chimpanzee, Orang, and Gibbon, 
it may be remarked that the globular cranium of the last, and its superior size com- 
pared with the jaws and teeth, seem to show the Gibbons to be more nearly akin to 
Man than are the larger tailless Apes; and this conclusion has been adopted by a 
distinguished French paleontologist, M. Lartet, and accepted by a geological authority 
at home’. They cite the experienced Professor of Human Anatomy at Amsterdam as 
supporting this view; but I have failed to find any statement of the grounds upon 
which it was sustained. In the article “‘ Quadrumana”’ of Todd’s ‘ Cyclopedia of Ana- 
tomy,’ cited by Lartet*, Prof. Vrolik briefly treats of the osteology of the Quadrumana 
according to their natural families. In ‘‘ a first genus, Sima proper, or Ape,” he in- 
cludes the Chimpanzee or Orang, noticing some of the chief points by which these 
Apes approach the nearest to Man. He next goes to ‘‘ the second genus, the Gibbons” 
(Hylobates) ; he notices their ischial callosities, and the nearer approach of their molars, 
in their rounded form, to the teeth of Carnivora than the molars of the genus Simia. 
Then, comparing the Siamang with other species of Hylobates, Vrolik says, ‘its skeleton 
approaches most to that of Man ’”’—which may be true in comparison with other Gibbons, 
but certainly is not so as respects the higher Simie. No details are given to illustrate 
the proposition even in its more limited application ; but the minor length of the arms 
in the Siamang, as compared with Hylobates lar, was probably the character in 
point. 
The appearance of superior cerebral development in the Siamang and other long- 
armed Apes is due to their small size and the concomitant feeble development of their 
jaws and teeth. ‘The same appearance makes the small platyrrhine Monkeys of South 
America equally anthropoid in their facial physiognomy, and much more human-like 
than are the great Orangs and Chimpanzees. It is an appearance which depends upon 
the precocious growth of the brain as dependent on the law of its development. In all 
Quadrumana the brain has reached its full size before the second set of teeth is acquired 
—almost before the first set is shed. If, however, a young Gorilla, Chimpanzee, or 
Orang be compared with a young Siamang of corresponding age, the absolutely larger 
size and better shape of the brain, the deeper and more numerous convolutions of the 
cerebrum, and the more completely covered cerebellum in the former, unequivocally 
demonstrate the higher organization of the shorter-armed Apes. ‘‘ In the structure of the 
brain,” writes Vrolik®, in accordance with all other comparative anatomists, ‘‘ they ”’ 
(Chimpanzee and Orang-utan) ‘‘ approach the nearest to Man.” The degree to which 
the Chimpanzee and Orang so resemble the Human type seemed much closer to Cuvier, 
‘ Sir C. Lyell, ‘ Supplement to the Fifth Edition of a Manual of Elementary Geology,’ 1859, p. 15. 
? Comptes Rendus de l’Académie des Sciences, Juillet 28, 1856. 
3 Art. Quadrumana, ‘ Cyclopedia of Anatomy,’ vol. iv. p. 195. 
