1 855.] A nthropoid Apes, and tJieir relations to Man. 3 1 



the head ; and the sagittal ones in reference to an increased extent of 

 the temporal muscles. The zygomatic arches are strong, and well 

 arched outwards. The lower jaw is of great depth, and has powerful 

 ascending rami, but the chin is wanting. The facial angle is about 

 50° to 55° in the full-grown simia satyrus, and 55° to 60° in the 

 troglodytes niger. The difference in the facial angle between the 

 young and adult apes, (which, in the young chimpanzee, approaches 

 60° to Q^"^,) depends upon those changes consequent upon the shed- 

 ding of the deciduous teeth and the concomitant development of the 

 jaws and intermuscular processes of the cranium. 



But the knowledge of the species of these anthropoid apes has been 

 further increased since the acquisition of a distinct and precise cog- 

 nisance of the characters of the adults of the orang and chimpanzee. 

 First, in reference to the orangs of Borneo, specimens have reached 

 this country which show that there is a smaller species in that island, 

 the Simia Morio, in which the canines are less developed, in which 

 the bony cristce are never raised above the level of the ordinary con- 

 vexity of the cranium, and in which the callosities upon the cheeks 

 are absent, associated with other characteristics plainly indicating a 

 specific distinction. The Rajah Brooke has confirmed the fact of 

 the existence in the island of Borneo of two distinct species of red 

 orangs ; one of a smaller size and somewhat more anthropoid ; and 

 the larger species presenting the baboon-like cranium. 



In reference to the black chimpanzee of Africa also, another very 

 important addition has been made to our knowledge of those forms 

 of highly developed quadrumana. In 1847 Professor Owen received 

 a letter from Dr. Savage, a church-missionary at Gaboon, enclosing 

 sketches of the crania of an ape, which he described as much larger 

 than the chimpanzee, ferocious in its habits, and dreaded by the 

 negro natives more than they dread the lion or any other wild 

 beast of the forest. These sketches showed plainly one cranial 

 characteristic by which the chimpanzee differs in a marked degree 

 from the orangs ; viz. that produced by the prominence of the 

 supra-orbital ridge, which is wanting in the adult and immature of 

 the orangs. That ridge was strongly marked in the sketches trans- 

 mitted. At a later period in the same year, Mr. Stuchbury trans- 

 mitted to the Professor from Bristol two skulls of the same large 

 species of chimpanzee, received from the same locality in Africa, 

 bringing clearly to light evidence of the existence in Africa of a 

 second larger and more powerful ape, — the troglodytes gorilla. 

 This species presents the characters of the cranium which are seen 

 in the immense development of the occipital and parietal cristae in 

 relation to the muscles of the neck and jaws, — repeating, and even 

 exaggerating, the prominence of the supra-orbital ridges of the 

 chimpanzee, and showing the same characteristic inequality in the 

 development of the teeth, particularly in the exaggerated size of the 

 canine teeth, as in the great pongo of Wurmb. But the gorilla 

 differs from the orang, and resembles man, first in the minor develop- 



