170 SKELETON OF THE PIG 



is deeply notched. The condyle is concave in the transverse direction. The post- 

 glenoid process is absent, but the articular surface is bounded behind and medially 

 by a crest. There is no temporal canal. The external acoustic meatus is very 

 long and is directed dorso-laterally. The bulla ossea is large, compressed laterally, 

 and bears a pointed muscular process in front. A narrow space intervenes between 

 the bulla and the basilar part of the occipital bone, so that the foramen lacerum 

 resembles that of the horse. The small hyoid process is situated in a deep de- 

 pression in front of the root of the paramastoid process, and the stylo-mastoid 

 foramen is lateral to it. The petrous part presents no important differential fea- 

 tures. The squamous part (including the root of the zygomatic process) contains 

 an air-cavity, which is continuous with the sphenoidal sinus. 



The sphenoid bone is short and resembles that of the ox in general. The body 

 is narrow. The hypophyseal or pituitary fossa is very deep, and is limited behind 

 by a prominent dorsum sellse; the dorsum bears lateral projections, the posterior 

 clinoid processes (Processus clinoidei aborales). 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 bones 

 in the formation of the pterygoid fossa (Fossa pterygoidea) , which opens backward 

 and is not present in the horse or ox. The sphenoidal sinus is very large and oc- 

 cupies the body, the temporal wings, and a great part of the pterygoid 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- 

 teiisive 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 endoturbinates and eighteen 

 ectoturbinates (Paulli). The lamina lateralis concurs in the formation of the 

 pterygo-palatine fossa. The lamina transversalis separates the fundus of the 

 nasal cavity from the naso-pharyngeal meatus. 



Face 



The maxilla is extensive. Its facial 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 (Juga canina) at the anterior end which is very pronounced 

 in the boar. The facial crest extends forward from the root of the zygomatic proc- 

 ess and fades out behind the infraorbital foramen; in some specimens it is prom- 

 inent and thin-edged, in others it is rounded and projects little. The zygomatic 

 process is short but stout and buttress-like; it is overlapped laterally by the malar. 

 The maxillary 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 transverse grooves (Sulci palatini transversi) 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 infraor- 

 bital 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 



