142 SKELETON OF THE PIG 



is narrow. The pituitary fossa is very deep, and is limited behind In^ a prominent 

 dorsum sellse; the dorsum bears lateral projections, the posterior clinoid processes. 

 The foramen ovale is absent, being included in the foramen lacerum anterius. 

 The other foramina are like those of the ox. The pterygoid process is broad and 

 twisted. Its base is not perforated and its free edge is thin and sharp. It concurs 

 with the pterygoid and palate l)ones in the formation of the pterygoid fossa, which 

 opens backward and is not present in the horse or ox. The sphenoidal sinus is 

 very large and occupies the body, the temporal wings, and a great part of the ptery- 

 goid processes in the adult; it is continued into the temporal bone as mentioned 

 above. 



.The ethmoid bone has a relatively long perpendicular plate, which is marked 

 by ridges corresponding to the ethmoidal meatuses. The cribriform plate is ex- 

 tensive and very oblique, so that it and the crista galli are almost in line with the 

 basi-cranial axis. A linear series of relatively large foramina is found on either 

 side of the crista. The lateral mass consists of five endoturl^inals and eighteen 

 ectoturbinals (Paulli). The lamina papyracea concurs in the formation of the 

 ptery go-palatine fossa. 



Face 



The maxilla is extensive. Its external surface forms a longitudinal groove, 

 which is continued upon the premaxilla in front and the facial parts of the lacrimal 

 and malar behind. The infraorbital foramen — sometimes double — is large and 

 is situated above the third or fourth cheek tooth. The alveolus for the canine 

 tooth produces a ridge at the anterior end which is very pronounced in the boar. 

 The facial crest extends forward from the root of the zygomatic process and fades 

 out behind the infraorbital foramen; in some specimens it is prominent and thin- 

 edged, in others it is rounded and projects little. The zygomatic process is short 

 but stout and buttress-like; it is overlapped externally by the malar. The maxil- 

 lary tuberosity forms in the young subject a long bulla, which occupies most of the 

 pterygo-palatine fossa and contains the developing permanent molars; after the 

 eruption of the teeth the tuberosity flattens and joins the vertical part of the palate 

 bone. The palatine process is very long and is marked in its anterior part by trans- 

 verse ridges corresponding with those of the mucous membrane of the palate. 

 The anterior palatine foramen is near the junction with the palate bone; from it the 

 palatine groove can be traced distinctly along the entire length of the process. 

 The alveolar border presents a large alveolus for the canine tooth at its anterior 

 end; behind this are seven alveoli for the cheek teeth, which increase in size from 

 first to last. The maxillary foramen and infraorbital canal are very large. The 

 maxillary sinus is small. 



The body of the premaxilla is narrow and prismatic. It presents three alveoli 

 for the incisor teeth, which are separated by short intervals and diminish in size 

 from before backward. As in the ox, a narrow space separates the right and left 

 bones and takes the place of the foramen incisivum. The palatine process is long 

 and narrow. The nasal process is very extensive and is somewhat rhomboid in 

 outline. Its upper border forms a very long suture with the nasal ])one, and the 

 lower articulates to about the same extent with the maxilla. The palatine fissure 

 is relatively wide. 



The horizontal part of the palate bone forms a fourth to a fifth of the length of 

 the palate; its palatine surface is triangular, the apex being anterior; its nasal 

 surface is deeply grooved and smooth. A pterygoid process (processus pyramidalis 

 of man) projects backward and downward, and its thick rounded end is received 

 between the pterygoid process of the sphenoid and the pterygoid bone. The 

 perpendicular part is largely overlapped externally by the maxilla and concurs in 

 forming part of the palatine canal. Superiorly the two plates separate and inclose 



