476 



ANATOMY OF VERTEBRATES. 



325 



the upper surface of the skull ; the osseous horn-cores are 

 originally distinct^ v,ith their bases crossing the coronal suture, 



and resting equally upon the parietals 

 and frontals : they, however, coalesce 

 therewith in old males, and the frontal 

 and parietal sinuses extend into the 

 lower fourth, the rest of the horn-core 

 being a solid and dense bone. The pro- 

 tuberance upon the frontal and contigu- 

 ous parts of the nasal bones is due to 

 an enlargement of those bones (as ob- 

 vious in the section, fig. 326), and not 

 to any distinct osseous part : its surface 

 is roughened by vascular impressions, 

 undermining the basal periphery and 

 simulating a suture. The lacrymal is 

 separated from the nasal by a large 

 vacuity intervening between those 

 bones, the frontal and the maxillary. 

 The premaxillaries, which are of un- 

 usual length, articulate with the nasals. 

 The petro-tympanic is a separate bone. 

 The symphysis of the lower jaw is 

 unusually long and slender. The arti- 

 cular surface of the prominent occipital 

 condyles is so extended vertically as 

 to admit of the head beino' raised into a line with the neck, and 



Skull of female GirafiEe. 



Section of Skull of male Giraffe. 



