SKELETON AND TEETH 65 



proportions in different mammals ; in those which have a 

 proboscis, hke tapirs and elephants, or a much inflated snout, 

 such as the Moose (Alee) or the Saiga Antelope (Saiga tatarica) 

 the nasals are always very much shortened and otherwise 

 modified in form. 



The anterior end of the skull is formed by a pair of rather 

 small bones, the premaxillaries, which carry the incisor teeth ; 

 they bound the sides of the nasal opening, or anterior nares, 

 reaching to the nasals, when the latter are of ordinary length ; 

 they also form the front end of the hard or bony palate, which 

 divides the nasal passage from the mouth. The jnaxillaries, 

 or upper jaw-bones, make up nearly all of the facial region on 

 each side and send inward to the median line from each side 

 a bony plate which together constitute the greater part of the 

 hard palate ; the remainder of the upper teeth are implanted 

 in the maxillaries. A varying proportion of the hinder part 

 of the hard palate is formed by the palatines, which also en- 

 close the posterior nares, the opening by which the nasal passage 

 enters the back part of the mouth. The maxillary of each 

 side extends back to the orbit, which it bounds anteriorly and 

 in the antero-superior border of which is the usually small 

 lachrymal. The inferior, and more or less of the anterior, 

 border of the orbit is made by the cheek-bone {malar or jugal) 

 which may or may not have a postorbital process extending 

 up toward that of the frontal ; when the two processes meet, 

 the orbit is completely encircled by bone, but only in monkeys, 

 apes and Man is there a bony plate given off from the inner 

 side of the postorbital processes, which extends to the cranial 

 wall and converts the orbit into a funnel-shaped cavity. For 

 most of its length, the jugal projects freely outward from the 

 side of the skull and extends posteriorly beneath a similar bar 

 of bone, the zygomatic process of the squamosal. This process 

 and the jugal together constitute the zygomatic arch, which on 

 each side of the skull stands out more or less boldly, and the 

 size and thickness of which are subject to great variation in 



