206 THE SKULL. [CHAP. 



The most remarkable feature in the face is the form and 

 position of the anterior narial orifice (an). It is wide trans- 

 versely, very short from above downwards, placed very high, 

 and is directed upwards and forwards, almost as much as in 

 the Whalebone Whales. The nasal bones (JVa) which bound 

 it above are very thick, short, broad behind, and conical 

 in front, and contain large air-cavities. The inferior and 

 lateral margins of the orifice are formed entirely by the pre- 

 maxillae (PMx\ which send processes up to join the nasals 

 and frontals. In front of the nares the face is prolonged 

 into a somewhat quadrate, depressed, alveolar process, trun- 

 cated in front, concave above, rounded laterally, formed by 

 the premaxillas above and at the sides, and by the maxillae 

 below. This contains the roots of the great incisor teeth 

 or tusks. 



The lacrymal is small, placed almost entirely within 

 the margin of the orbit, and ends anteriorly in a projecting 

 antorbital process. The zygomatic arch is slender and 

 straight, the malar being small, and forming only the middle 

 part of the arch, the anterior portion of which is (unlike 

 that of all Ungulates) formed by the maxilla. 



The elongated, tubular nasal cavity forms a sigmoid 

 curve, being directed (from below) at first forwards, then 

 upwards, then forwards. The olfactory chamber is a 

 comparatively small fossa in the middle third of its posterior 

 wall, filled by the complex ethmoturbinals. The maxillo- 

 turbinals are but rudimentary, the narial passage being quite 

 free. 1 The floor of the palate is completed posteriorly by 

 well-developed palatines (PI). The pterygoid (Pi) is slender 

 and very early ankylosed with the pterygoid process of the 



1 The elongated proboscis probably supplies their place functionally 

 in warming and cleaning the inspired air. 



