786 



Gorilla. But even in the low race of Man selected for the comparison, the development of 

 the prosencephalon carries the interorbital part of the frontal forward so as to bring the 

 orbital cavity into view in advance of its lateral malar boundary ; but no part of that cavity 

 is seen in the same direct side view in the Chimpanzee. The prominent nasal bone forms part 

 of the anterior outline below the overarching frontal in Man ; but notwithstanding the cha- 

 racteristic projection of the nasal in the great Gorilla, the thick swollen external wall of the 

 orbit shuts it out of view. Below the malar the alveolus of the great canine in the maxillary, 

 and then the prominent premaxillary and incisors, complete the anterior contour in the Go- 

 rilla ; but in Man the concave maxillary border of the external nostril leads from the nasal 

 to the short and slightly projecting anchylosed premaxillary bone, supporting the almost ver- 

 tical crowns of the incisors. The great cuspidate canine, the interval dividing it from the 

 incisors, the superior size of the first premolar over the second, the prominent double socket 

 for the two diverging external fangs of each premolar, and the equal-sized true molars, are 

 all distinctive characters in the Gorilla of the most decisive nature in contrast with the spe- 

 cific peculiarities of the dentition in Man. In the direct side view of the human skull, a part 

 only of the crown of the outer incisor and scarcely any of the inner incisor can be seen pro- 

 jecting beyond the canine ; whilst the whole crown of the outer incisor and the more promi- 

 nent part of the inner incisor extend into view beyond the canine in the Gorilla. The whole 

 alveolar border of the upper jaw extends much further below the base of the cranium in the 

 Gorilla than in Man, in whom the superior depth of the brain-case brings the mastoid pro- 

 cess almost on a level with the alveoli of the maxillary bone. The relatively shorter, deeper, 

 subquadrate form of the upper jaw is also a marked characteristic of Man. In the Gorilla, 

 although the alveolar border forms a right angle with the posterior border of the upper jaw, 

 the long anterior border slopes forwards towards the lower border at an acute angle, and to 

 the same degree departs from its parallelism with the posterior border. The spheno-maxil- 

 lary fissure is longer, narrower and less curved in the Gorilla than in Man : the ectopterygoid 

 is shorter, but the antero-posterior extent of the base of this process is relatively much 

 greater. The styliform process of the sphenoid terminates the arch behind the pterygoid in 

 both ; but the vaginal process with its anchylosed stylohyal is a character quite peculiar to 

 the human skull. 



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 fora- 

 men of the human skull from that in the Gorilla 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 Gorilla, 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. The thick superorbital ridge and outstand- 

 ing malars and maxillaries compose the major part of the plane, and the prognathic premax- 

 illaries 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 



