■82 PROFESSOR OWEN ON THE OSTEOLOGY OF 



where the upper extremity of the premaxillary remains, as a distinct ossicle, detached 

 from the coalesced part of the bone, in the present variety from the river Danger. The 

 vomer (is) appears to be less completely ossified in the Gorilla than in Man. 



The inferior turbinal (19) is a large thin rhomboidal plate, slightly convex towards 

 the median line, terminating in a straight margin below, and by a long oblique margin 

 in front, which joins a reflected thin plate of the maxillary, bounding the fore part of 

 the lacrymal fossa, an inch behind the external nostril. 



The middle turbinal (is) resembles in its simple shape the lower one, but is smaller ; 

 the still smaller upper plate is bent, but not convoluted. The ' lamina perpendicularis 

 aethmoidei ' (u) is of much less extent than in Man. 



The cranium of the adult Orang {Pithecus Satyrus) when bisected (PI. XXIX. fig. 1), 

 as in the foregoing specimens, presents a close general resemblance to that of the Go- 

 rilla, and the same wide diff'erences in the proportions of the cranial and olfactory cavi- 

 ties from that of the Papuan. 



The brain-chamber is shorter, but higher, than in the Gorilla, and though there is but 

 two lines' breadth difference in favour of the Orang in the latter diameter, it appears to 

 be proportionally greater on account of the less antero-posterior extent of the chamber, 

 which in the Gorilla is 5 inches 2 hues, whilst in the Orang it is only 4 inches 3 lines. 



In. Lines. 

 The greatest vertical diameter (in front of the foramen 



magnum) in the Orang is 3 5 



Ditto in the Gorilla 3 3 



Ditto in the Papuan 5 



Ditto in the European 5 6 



The rhinencephalic compartment (PI. XXIX. rh) is somewhat narrower, and is as 

 deep in the Orang as in the Gorilla : the ' crista galU ' is equally rudimental. The 

 division of the prosencephalic compartment, for the anterior and middle lobes of the 

 cerebrum, is as ill defined. 



The tentorial ridge is not continued backwards beyond the petrosal, as in the Gorilla. 

 The basisphenoid has coalesced with the basioccipital, and is of less extent. 



The sphenoidal sinus is almost wholly formed by the presphenoid, and it is divided 

 by a longitudinal horizontal, instead of by a vertically transverse septum, as in the Go- 

 rilla. The lower border of the basi-occipito-sphenoidal floor of the cranium has the 

 same parallelism with the bony palate or floor of the nostrils as in the Gorilla. The 

 plane of the occipital foramen forms a somewhat less open angle with the straight basi- 

 occipito-sphenoidal line than in the Gorilla, and to that extent departs further from 

 Man. The interorbital sinuses (/) do not ascend to within half an inch of the upper 

 level of the orbits ( u '), and there is consequently no proper frontal sinus : a cancellous 



