AND AFFINITIES OF THE GORILLA. 261 



Finally, a portion of a lower jaw with teeth and the shaft of a humerus of a quadru- 

 nianous animal {Dryopithecus), equalling the size of those bones in Man, have been 

 discovered by M. Fontan, of Saint-Gaudens, in a marly bed of upper miocene age, 

 forming the base of the plateau on which that town is built. The molar teeth present 

 the type of grinding surface of those of the Gibbons (Hylobates), and, as in that genus, 

 the second true molar is larger than the first, not of equal size, as in the Human 

 subject and Chimpanzee. The premolars have a greater antero-posterior extent, rela- 

 tively, than in the Chimpanzee, and in this respect agree more with those in the Sia- 

 mang. The first premolar has the outer cusp raised to double the height of that of the 

 second ; its inner lobe is less developed than in the Gorilla, certainly less than in the 

 Chimpanzee. The posterior talon of the second premolar is more developed, and con- 

 sequently the fore-and-aft extent of the tooth is greater, than in the Chimpanzee ; 

 thereby the second premolar of Dryopithecus more resembles that in Hylobates, and 

 departs further from the Human type. 



The canine, judging from the figures published by M. Lartet', seems to be less deve- 

 loped than in the male Chimpanzee, Gorilla, or Orang, in which character the fossil, 

 if it belonged to a male, makes a nearer approach to the Human type ; but it is one 

 which many of the inferior Monkeys also exhibit, and is by no means to be trusted as 

 significant of true afiinity, supposing even the sex of the fossil to be known as being 

 male. 



The shaft of the humerus, found with the jaw, is peculiarly rounded, as it is in the 

 Gibbons and Sloths, and oflfers none of those angularities and ridges which make the 

 same bone in the Chimpanzee and Orang come so much nearer in shape to the humerus 

 of the Human subject. The fore part of the jaw, as in the Siamang, is more nearly 

 vertical than in the Gorilla or Chimpanzee ; but whether the back part of the jaw may 

 not have departed in a greater degree from the Human type than the fore part ap- 

 proaches it, as is the case in the Siamang, the state of the fossil does not allow of de- 

 termining. One significant character is, however, present — the shape of the fore part 

 of the coronoid process. It is slightly convex forwards, which causes the angle it forms 

 with the alveolar border to be less open. The same character is present in the Gib- 

 bons. The front margin of the lower half of the coronoid process in Man is concave, 

 as it is likewise in the Gorilla and Chimpanzee. I am, however, acquainted with this 

 interesting fossil, referred to a genus called Dryopithecus, only by the figures published 

 in the 43rd volume of the ' Comptes Rendus de I'Academie des Sciences.' From these 

 it appears that the canine, two premolars, and first and second true molars are in 

 place ; the socket of the third molar is empty, but widely open above ; from which it 



closely resembled those o£a small Macacus (September 1839, Magazine of Nat. Hist. p. 446), have since been 

 matched by the lower molars of the extinct genus Hyracotherium, subsequently discovered, and determined by 

 the dentition of both upper and lower jaws. (Annals of Nat. Hist. 1841 & 1862.) 

 ' Comptes Rendus de I'Academie des Sciences, Paris, vol. xUii. 



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