787 



behind and beyond the outer walls of the orbits, and the mastoid processes come into view 

 behind the angles between the malars and maxillaries. 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 Gorilla ; 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 Go- 

 rilla the lacrymal 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 lacrymal is much smaller 

 as compared with the part excavated for the lacrymal 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 ex- 

 panded vault of the cranium in Man ; the narrower temples of the Negro and Australian 

 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 Gorilla the whole length of the face from the lower border of the orbits is seen 

 sloping from beneath the superorbital ridge ; the whole span of the large zygomatic arches, 

 with parts of the temporal fossae, appear at the sides of the narrower temples ; the oval cra- 

 nial vault after a certain expanse changes its curve, and from being convex becomes concave, 

 expanding into a broad base formed by the superorbital ridge in front and by the lambdoidal 

 crest behind, continued into the zygomatic arches at the sides. The small cranial dome also 

 supports the strong sagittal crest which at the coronal suture divides and diverges, curving 

 outwards to the external angles of the superorbital ridge. No qnadrumanous animal, and 

 few other mammals, offer a greater contrast with Man in the form and structure of the upper 

 surface of the cranium than the great male Gorilla does. 



In the basal comparison of the skulls the basioccipital is longer, thicker vertically, flatter 

 below, and broader in front than in Man ; it sends out a short precondyloid process into the 

 jugular foramen on each side ; these are overlapped by the synonymous processes of the 

 petrosal anterior to the precondyloid holes : the basioccipital does not anchylose with the 

 basisphenoid ; both extend straight forwards, parallel to the plane of the palate, iustead of 

 curving from below upwards and forwards as in Man. The_/?*<ra lacera media, which di- 

 vides the basioccipital from the petrosal, is longer and narrower, and does not expand at its 

 fore part : the posterior border of the basioccipital becomes less expanded where it joins the 

 condyles. The occipital condyles are much smaller compared with the size of the skull than 

 in Man ; they are also less convex and more rounded at then" extremities ; they are wider 

 apart, and their axes diverge at a more open angle from before backwards. The posterior 

 condyloid fossa extends forwards along the outer side of the condyle to the jugular process ; 

 in Man it usually terminates in a postcondyloid foramen, and is filled up by the rough par- 

 occipital ridge which sometimes developes a small (paroccipital) process ; this is represented 



5 H 2 



