470 THE ANATOMY OF VEETEBRATED ANIMALS. 



mandible is mucli lai'ger than tlie ascending portion, in 

 accordance witli the great production of the upper jaw, and 

 the consequent low facial angle. In many of the Cyno- 

 cephali, longitiidinal osseous ridges are developed upon the 

 maxillae, and greatly increase the brutishness of their 

 aspect. Sagittal and lambdoidal crests may appear along 

 the lines of the corresponding sutures. There is no dis- 

 tinct mastoid process ; and the styloid process is not 

 ossified. The parietal bones do not unite with the alisphe- 

 noids, being separated from them by the union of the 

 squamosals with the frontals. The brain case is flattened 

 and elongated, and the convex roofs of the orbits project 

 into it and greatly diminish the capacity of its frontal 

 portion. The olfactory fossae are veiy deep, and sometimes 

 almost tubular. The two frontal bones send thick processes 

 across the base of the skull, which unite over the junction 

 of the presphenoid and the ethmoid, and thus narrow the 

 entrance to the olfactory fossae. The basicranial axis is 

 shorter than the cerebral cavity, but is still proportionally 

 long. The occipital foramen lies in the posterior sixth of 

 the base of the skull, and it looks obliquely backwards and 

 downwards. The premaxillo-maxillary suture never dis- 

 appears until long after the second dentition is complete, 

 and may persist throughout life. The palate is long and 

 narrow. The nasal bones are flat, and early ankylose into 

 one bone. 



The scapula is relatively longer and narrower than that 

 of Man ; but the spine lies at right angles to the vertebral 

 border, and the supra- spinous, is much smaller than the 

 infra-spinous fossa. 



The axis of the ai'ticular head of the humerus is not 

 dii-ected upwards and inwards, but upwards and backwards; 

 the bicipital groove lies on the inner side ; and the shaft of 

 the bone is so bent that it is convex forwards. In all these 

 characters the fore limb shows its relation to the function 

 of support. The radius exhibits modifications which have 

 the same signification. Its proximal head is transversely 

 elongated, and lies somewhat in advance of the ulna, 



