OMNIVORA VERTEBRAE. 107 



springs the tusk ; the alveoli for the molar teeth, usually seven in number, 

 gradually increase in size, from the anterior one, which is very small, 

 to the last, largely developed and strong. ' The maxillary sinus is small, 

 projecting into the malar bone ; the palatine foramen opens on the 

 palatine plate of the maxilla, before the palatine bone. The premaxilla 

 is large and strong ; it is not joined at the symphysis, and consequently 

 forms no foramen incisivum ; its external process is very long, and articu- 

 lates largely with the nasal bone ; there are three alvfeoli on each side for 

 the incisor teeth. Part of the septum of the nose becomes ossified, forming 

 the prenasal or snout bone (os rostri). The anterior nares are small and round. 



The palatine bones form a large portion of the bony palate ; their orbital 

 portion is very small. The palatine ridge is replaced by a tuberosity, with 

 "which the pterygoicT process' of the sphenoid bone articulates externally, and 

 the pterygoid bone internally, and the union of these three parts results in a 

 large trifid tubercle. 



The tiLrhinals are longer and less fragile than in the horse. 



The inferior maxilla is very strong, having no well-defined neck; and small ^ 

 interdental spaces ; the coronoid process is short, but strong, and the condyles, 

 somewhat nodular, are compressed laterally. The dental canal terminates 

 anteriorly by numerous small mental foramina ; and the alveoli for the molars 

 are seven in number. Posteriorly this bone bears a cert^ain resemblance to the 

 corresponding human bone. The symphysis becomes' early ossified in this 

 animal. 



The OS hyoides has a large body, but no appendix. The cornicula are short, 

 while the cornua are thin, twisted somewhat like the letter S, and united 

 to the temporal bones by elastic ligaments. 



Fig. 30. 

 longitudinal Section of a Hog's Skull. 1, Os rostri; 2, Maxillary Tar- 

 binal ; 3, Frontal Turbiaal ; 4, Large Ethmoidal yolute; 5, Occipital Styloid 

 process; 6 C 6", Frontal Siuiis; 7, ^asal chamber: S 8', Cranial cavity; 

 9, Auditory bulla. 



VERTEBHiE. 



The true vertebral column consists of 28 vertebrce.— 7 cervical, 14 dorsal, and 

 7 lumbar. The cervical vcrlchrce are very short, convex below, and without 

 inferior spines ; the transverse processes are bifid, and, excepting the last, the 

 posterior ones are large and overlapping. The articular processes are strong, 

 the anterior being pierced by a foramen entering the spinaL canal. The 

 transverse processes are small and generally pierced by vertebral foramina. 

 The atlas is strong, rough, and irregular, presenting a large tuberosity en its 

 superior surface ; the wings are strong, particularly at their posterior borders; 



