762 



nium is parallel with the bony palate or floor of the nostrils. The plane of the occipital 

 foramen forms an open angle with the straight basi-occipito-sphenoidal line. The inter- 

 orbital sinuses do not ascend to within half an inch of the upper level of the orbits, and there is 

 consequently no proper frontal sinus : a cancellous structure occupies the usual place of this, 

 below which, the part of the interorbital septum formed by the hinder crista of the nasal 

 bone and the frontal presents a very compact dense structure. The small venous canal con- 

 tinued from the foramen caecum traverses the base of this septum to terminate at the lower 

 end of the short nasal bone. The lamina perpendicularis sethmoidei presents a quadrate form 

 eight lines in diameter. The floor of the nasal cavity is long and thick, as compared with 

 that in Man, and a larger proportion of it is contributed by the premaxillary. The part of 

 the premaxillary divided by the section is absolutely longer, larger, and more nearly parallel 

 with the palato-nasal plate of the maxillary than in the Gorilla (No. 5178). The nasal end 

 of the incisive canal is divided by the process extending from the premaxillary to the maxil- 

 lary ; but this is the only part of the premaxillary which has not coalesced with the maxil- 

 lary ; every other trace of the original suture has disappeared, even that on the palate. 

 There is no production of the nasal below the crista sent backwards to form the dense inter- 

 orbital septum, and no production of the feebly-marked superorbital boundary, forwards and 

 upwards, to form a crest, as in the Gorilla. The turbinal plates are less developed than in 

 the Gorilla ; the lower one is shorter than the one above ; and there is not any plate answer- 

 ing to the small superior turbinal in the Gorilla and in Man. Both lambdoidal and sagittal 

 cristae are much less developed than in the Wurmbian variety of Orang. There is a rudi- 

 mental styloid process, formed by the anchylosed base of the stylohyal, which is defended in 

 front by a low and obtuse vaginal process. 



Presented by Sir James Brooke, Rajah of Sarawak. 



5055. The lower jaw, vertically bisected at the symphysis, of the same Orang-utan 

 (Pithecus Satyr us). 



The compact wall of the symphysis is thick and dense. The symphysis slopes from above 

 downwards and backwards. The outer alveolar process of the second premolar (p 4) has 

 been partially absorbed in both rami. 



Presented by Sir James Brooke, Eajah of Sarawak. 



5056. The skull of an adult female Orang-utan (Pithecus Satyr us, of the variety 

 called ' Mias Rambi '). 



The roots of the teeth are exposed on the right side of both jaws, showing that the pre- 

 molars as well as the true molars are implanted by three distinct fangs, two external and one 

 internal. The back part of the cranium has been mutilated by the removal of a great part 

 of the superoccipital. In the interior of the cranium it may be observed that the petrosal 

 has no cerebellar pit : the posterior clinoid processes have not only coalesced with each other, 

 forming a bony arch above the basisphenoid, but have also coalesced with the anterior clinoid 

 processes, forming arches above the sides of the sella turcica. The inward projection of the 

 orbits gives great depth to the intermediate contracted rhinencephalic fossa, in the bottom of 



