he freely admitted that the Gorilla strikes the observer as being a 

 much more bestial and brutish animal than the Chimpanzee. All the 

 features that relate to the wielding of the strong jaws and large 

 canines are exaggerated ; the evidence of brain is less, its chamber is 

 more masked by the outgrowth of the strong occipital and other 

 cranial ridges. But the impression so made — that the Gorilla is 

 less like Man — is the same which is derived from comparing a young 

 with an adult Chimpanzee, or some small tailless monkey with a full- 

 grown male Orang or Chimpanzee. Taking the characters that cause 

 that impression at a first inspection of the Gorilla, most of the small 

 South American monkeys are more anthropoid than it ; they have a 

 proportionally larger and more human-shaped cranium, much less 

 prominent jaws, with more equable teeth. 



Referring to the skeletons of the adult males of the Gorilla, Chim- 

 panzee, Orang, and Gibbon, Professor Owen remarked that the glo- 

 bular cranium of the last, and its superior size compared with the 

 jaws and teeth, seemed to show the Gibbons to be more nearly akin 

 to man than are the larger tailless Apes. And this conclusion had 

 been adopted by a distinguished French palaeontologist, M. Lartet, 

 and accepted by a high geological authority at home*. They cite the 

 experienced Professor of Human Anatomy at Amsterdam as support- 

 ing this view ; but Prof. Owen had failed to find any statement of 

 the grounds upon which it was sustained. In the art. Quadrumana 

 of Todd's " Cyclopaedia of Anatomy," cited by Lartet,^ Prof. Vrolik 

 briefly treats of the osteology of the Quadrumana according to their 

 natural families. In " a first genus, Simla 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 Simla. 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 Slmlce. No details are 

 given to illustrate the proposition even in its more limited appli- 

 cation ; but the minor length of the arms in the Siamang, as com- 

 pared 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 con- 

 comitant 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 gi'eat 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 ac- 

 quired, almost before the first set is shed. If, however, a young 



* Lyell, Sir C. " Supplement to the Fifth Edition of a Manual of Elementary 

 Geology," 1859, p. 15. 

 t " Comptes Rendus de I'Academie des Sciences, Juillet 28, 1856." 



