SKELETON OF PERISSODACTYLA. 



453 



The malar extends upon the face, beneath the lacrymal, in 

 advance of the orbit. The ascending ramus of the mandible has 

 a convex hind border curving from the condyle, 20, to beneath 

 the last alveolus, where it ends by a slight projection below the 

 inferior border of the horizontal ramus. The coronoid process, 

 19, is long, narrow, and recurved. 



305 



Hyoid arch, Horse. 



The stylohyals, fig. 305, st h, long and rib-like, articulate by a 

 rounded ^ head ' to the petromastoid ; expanding beyond this, 

 to form a sort of ^ tubercle,' and continued, slightly contracting, to 

 the short epihyal, e, p, h ; by means of which they articulate 

 with the ceratohyals, c, h ; which unite with the basihyal, b, h, 

 where this is joined to the thyrohyals, h, h. The basihyal 

 supports a glossohyal, g, h. The homology of the thyrohyals 

 with the ceratobranchials in Fishes and Batrachia is illustrated 

 by the figures B, h b, introduced (reversed) in the same cut. 



