OMNIVORA VEllTEBE.E. 107 



springs the tu.sk ; 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 prcmaxiUa 

 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 alveoli 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 arid 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, •witli 

 which the pterygoid 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 ttirbinals are longer and less fragile than in the horse. 



The inferior maxilla is very strong, having no Avell-defined heck, 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 nnmlier. Posteriorly this bone bears a certain resemblance to the 

 corresponding human bone. The symphysis becomes early ossified in thi.< 

 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. ■ • 



KiG. 30. 



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



binal; 3, Frontal Turbiual ; 4, Large Ethmoidal volute ; 5, Occipital Styloid 



process ; 6 C 6", Frontal Sinus ; 7, JS'asal chamber ; S 8', Cranial cavity ; 



9, Auditory Imlla. 



VERTEBRA. 



The true vertebral column consists of 28 vertebra?. — 7 cervical, 14 dorsal, and ' 

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

 inferior sj^ines ; 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 liy a foramen entering the spinal canal. The 

 transverse processes are small and generally pierced 1)V vertebral foramina. 

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

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



