94 



bdoidal ridges ; thus circumscribin2^ tlie origins of the temporal mus- 

 eles. The lambdoidal and mastoid ridges are broader and more de- 

 veloped than in the Chimpanzee, but inferior in both respects to 

 those of the Pongo. The inial region of the occ'ųmt is almost 

 smooth, and is convex, without the mesial ridge, and strong muscu- 

 lar imjiressions observable in the Pongo, \vhere a preponderating 

 weight in front calls for the insertion of powerful museles behind 

 to counterbalance it. 



The temporal bones join the frontai in Simia Morio as in the Ti-o- 

 glodytes niger; but this structure occiisionally is present on one or 

 both sides of the skull in Simia Satyrus. 



The udditamentum suturi lambdoidalis is present on both sides 

 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 \ve 

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

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

 foramen is also Icss obliąue than in the Pongo. The occii)ital condyles 

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

 dyloid yora?n«na are double on each side as in the Pongo: the carotid 

 andjugularybrff»i!waopen withinthe šame 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 lowcr 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 esternus 

 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 incisivvm 

 corresponds \vith the development of the incisive teeth, sho\ving the in- 

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

 panzee : the situation of the suturės 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 šame size as 

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

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

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

 literated in the more anthropoid Simia Morio. 



The os naši is a single narrow long triangular bone, slightly di- 

 lated at Its upper end or apex, vvith the basai margin entire, ])re- 

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

 been observed in škulis of the Chimpanzee. 



In the contraction of the interorbitai space, and the general 

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

 Simia Satyrus, but the orbitai cavity, as before obsers'ed, is smaller. 

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

 SimiuMorio resembles the Boniean species oi Pongo or Simia IVurmbii, 

 rather than the Simia Abtlii or Sumatran Pongo. 



l'he orbitai process of the os malce is perforated in the .S'. Morio 



