Mr. Owen oti the specific distinctions of the Orangs. 299 



in the -S. Morio, and the beginning of the lambdoidal suture may be 

 faintly traced, but the remainder is obliterated. 



Directing our attention to the base of the skull of S. Morio we 

 observe the occipital /oramew to be less posteriorly situated than in 

 the Pongo, but more so than in the Chimpanzee. The plane of the 

 foramen is also less oblique than in the Pongo. ITie occipital condyles 

 are as far apart anteriorly as in the Chimpanzee. The anterior con- 

 dyloid ybramiwa are double on each side as in the Pongo-. the carotid 

 and jugular/oramma open within the same depression; they are rela- 

 tively further apart in the Chimpanzee : the petrous portion of the 

 temporal bone, as in the Pongo, is relatively smaller than in the Chim- 

 panzee, and the articular cavity, or surface for the lower jaw, forms 

 a larger proportion of the base of the skull. 



The other characters of the basis cranii correspond with those 

 of the Pongo ; and the smaller size of the meatus auditorius externus 

 is probably associated in both species with a smaller auricle, as com- 

 pared with the Chimpanzee. 



On the bony palate the relative position of the foramen incisivum 

 corresponds with the development of the incisive teeth, showing the in- 

 termaxillary bones to be of larger size Tn the S. Morio than in the Chim- 

 panzee : the situation of the sutures joining these bones to the max- 

 illaries is indicated by vascular grooves, but otherwise obliterated ; 

 while in the cranium of a young Pongo of nearly the same size as 

 that of the Simia Morio, the intermaxillary sutures still remain, cor- 

 responding to the non- development of the permanent laniaries. It 

 will be interesting to determine at what period these sutures are ob- 

 literated in the more anthropoid Simia Morio. 



The OS nasi is a single narrow long triangular bone, slightly di- 

 lated at its upper end or apex, with the basal margin entire, pre- 

 senting no indications of original separation into two parts, as has 

 been observ^ed in skulls of the Chimpanzee. 



In the contraction of the interorbital space, and the general 

 form of the orbit and its boundaries, the Simia Morio resembles the 

 Simia Satyrus, but the orbital cavity, as before observed, is smaller. 

 In the plane of the orbit and straight contour of the upper jaw, the 

 Simia Morio resembles the Bornean species oi Pongo or Simia Wurmhii, 

 rather than the Simia Abelii or Sumatran Pongo. 



The orbital process of the os malce is perforated in the S. Morio 

 as in the Pongo, by several large foramina. ITiere is one principal 

 and two very small infraorbital /orflm2«a on either side ; the upper 

 maxillary bones are relatively smaller, as compared with the other 

 bones of the face, and especially the intermaxillaries, than in the Pow^ro; 

 a structure which coincides with the smaller proportional develop- 

 ment of the canine teeth. The nasal aperture has the same form as 

 in the adult Simia Wurmbii, being more elongated than in the imma- 

 ture Orang. 



The main and characteristic diiFerence then between the Simia 

 Morio and the Pongo, whether of Borneo or Sumatra, obtains in 

 the size of the laniary or canine teeth, to the smaller development of 

 which in the S. Morio, almost all the other differences in the cranium 



2Q2 



