172 THE GENERAL ANATOMY OF GORILLA [SECT. A 



They are rounded, and the lower margins of the nasal apertures are quite 

 indistinct. No definite nasal spine is seen, but sometimes a small tubercle 

 occurs and in a good many cases the prernaxilla throws oft' paired backwardly- 

 directed processes to meet the nasal septum : these processes must not be 

 mistaken for a true nasal spine, though suggestive of that structure. The 

 alveoli of the great canine teeth form projections on the facial surface on 

 each side of the nasal aperture. 



The palate has the characteristic long hypsiloid anthropoid contour, and 

 the post-palatine spine is commonly replaced by a notch. There is usually 

 some irregularity in the arrangement of the sutures on the palatine surface, 

 whereby the common cruciform appearance is distorted. The tuber maxillare 

 is small, and the anterior palatine foramen (whence the premaxillo-maxillary 

 sutures spring) is characterized by not including the lateral foramina (for 

 the anterior palatine arteries). 



The temporal fossa is very deep and capacious : the alisphenoid deeply 

 channelled, and often attenuated above, in correlation with the common 

 arrangement of a fronto-squamous articulation replacing the parieto-sphenoid 

 junction (of the Orang-utan, of Man, and of the Cebidae and Lemuroidea) : 

 herein some of the lower human races and the Cercopithecidae agree with 

 the Gorilla. 



The infra-temporal crest is very small, and the spheno-maxillary fissure 

 much narrowed as in the other Simiidae, which in this respect (and the con- 

 comitant approximate completion of the post-orbital wall) are more highly 

 specialized than Man or the Lemuroidea. Sometimes the malar bone does 

 not provide the end-boundary of the spheno-maxillary fissure, and then a 

 spheno-maxillary suture occurs. 



The base of the skull offers a few points worthy of special note. 

 Anomalous processes, such as the third occipital condyle, or ossification in 

 the suspensory ligament of the axis, and the like, are rare. The condyles 

 are short and the foramen smaller than in Man, even in skulls absolutely 

 larger than the human skull. The glenoid fossa is very shallow and to its 

 inner side is a great endo-glenoid tubercle. The anterior lacerate foramen 

 is commonly closed by osseous dejjosit, and the styloid process is diminutive. 

 The tympanic bone is long and semi-cylindrical, and has no " bullous " 

 inflation (Fig. 116 B). 



The teeth are of the typical number (|-f|§). The canines are enormous 

 in the males : the premolars have commonly three roots in the upper jaw ; 

 the molars bear four very clean-cut ("crystalline" Dr Keith calls them) cusps 

 in the maxilla; and in the mandible, a "talon" may bear two additional 

 cusps, despite the statements in certain works on this subject. The third 

 molar is already shewing signs of reduction in the maxilla (and the Chim- 

 panzee shews a further advance on this condition of reduction). Accessory 

 teeth are not uncommon. First in frequency come accessory molars in the 

 maxilla, then remnants or rudiments behind the premolars in the maxilla. 

 A unique case in the Hamburg museum shews a double canine tooth, and 



