406 PROFESSOR OWEN ON THE OSTEOLOGY OF 



Another feature peculiar to Man is the arch or upward curve of the basal contour 

 of the cranium between the occipital condyles and the lower end of the posterior border 

 of the vomer, and the near approach to parallelism of the line of the occiput below the 

 superior transverse ridge with the line of the teeth. The difference in the plane of the 

 occipital foramen of the human skull from that in the Chimpanzee is as well-marked in 

 the lowest as in the highest races of Man. 



Such is the enormous development of the facial part of the skull as compared with 

 the cranial part in the Chimpanzee, that in taking a direct front view with the nasal 

 cavity as the centre of the perspective plane, little more of the cranium is visible than 

 that which forms the base of the sagittal crest (PI. LXII. 7). The thick supraorbital 

 ridge (12) and outstanding malars (26) and raaxillaries (21) compose the major part of 

 the plane, and the prognathic premaxillaries (22) and incisors with the great canines 

 and their tumid alveoli complete with the broad and deep lower jaw the view below. 



In Man the upper half of the corresponding view is formed by the frontal part of the 

 cranial dome ; the expanded sides of that dome are visible behind and beyond the outer 

 walls of the orbits, and the mastoid processes come into view behind the angles between 

 the malars and maxillavies. Of the regular arch formed by the equable teeth only the 

 hinder molars are excluded from view, and not always these in the white races. 



The prominence of the entire nasal bones ; the relatively larger, broader, and more 

 sharply defined orbits ; their comparatively slender outer boundaries ; the concavity of 

 the surface which descends from the orbit to the alveoli of the premolars in contrast 

 with the convexity of the same part in the Chimpanzee ; the vertical plane of the nasal 

 aperture (which slopes from above downwards and backwards in more favoured races 

 of Man) ; and the slight prominence of the premaxillaries (which are vertical in well- 

 formed Caucasian skulls), are eminent characteristics of the human species in this 

 comparison. 



In the orbits of the Chimpanzee the lachrymal bones are either separated from the 

 ' ossa plana' or are united to them in a much smaller proportion than in Man ; and the 

 orbital plate of the lachrymal is much smaller as compared with the part excavated for 

 the lachrymal fossa than it is in Man. The entorbital angle or plate of the malar is 

 longer and extends deeper into the orbit than in Man. 



In a comparative view of the skulls from above, in which the beginning of the sagittal 

 suture is the centre of the perspective plane, scarcely anything is seen but the smooth 

 expanded vault of the cranium in Man ; the narrower temples of the Negro and Austra- 

 lian allow the zygomata to come into view, and in the most prognathic examples the 

 incisors just appear between the prominences of the frontal sinuses. 



In the Chimpanzee the whole length of the face from the lower border of the orbits 

 is seen sloping from beneath the supraorbital ridge ; the whole span of the large zygo- 

 matic arches, with parts of the temporal fossae, appear at the sides of the narrower 

 temples ; the oval cranial vault after a certain expanse changes its curve, and from 



