AND AFFINITIES OF THE GORILLA. 261 
Finally, a portion of a lower jaw with teeth and the shaft of a humerus of a quadru- 
manous 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 affinity, 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 offers 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 l’Académie 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 of,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.) 
1 Comptes Rendus de |’Académie des Sciences, Paris, vol. xliii. 
2m 2 
