60 



TBE BONES. 



Fig. 31. 



on itself in two different directions : from before to behind by its posterior border, and 

 behind to before by its anterior border. It is fixed to the supermaxillary bone by its 

 middle part, through the medium of a particular bony lamina, and it very incompletely 

 closes the excavation which concurs to form the maxillary sinus. In the skeleton 

 there is also'found behind, and at the base of this turbinated bone, a vast opening which 

 is totally closed in the fresh condition by the pituitary membrane. The maxillary sinus 

 is not prolonged in its interior. In the smaller ruminants, the cavity of the sinus is 

 closed by the maxillary turbinated bone in a more complete manner than in the Ox. 



15. Vomer. — This is a very large thin bone, resting only on the inferior half of the 

 median suture of the premaxillaries. 



16. PremaxiUary hone. — In the Ox, the inferior part of the 

 posterior border is convex, and cannot rest on a horizontal 

 plane by all its points at the Siime time. The condyle is 

 convex in its small diameter, and slightly concave laterally. 

 The coronoiil process is bent baokwHids and outwards. The 

 body does not show any alveolus for the tusk, because this 

 tnoth is absent in these animals ; but it is hollowed by eight 

 alveoli for the incisor teeth. The two branches of the bone 

 are never consolidated, but remain movable on each other 

 during life. 



17. Hyoid hone. — The hyoid bone of Ruminants is always 

 composed of seven pieces ; the styloid nucleus, whose presence 

 is not constant in solipeds, is never absent in these, and 

 assumes the proportions of a second small branch. The 

 anterior appendix is very short and thick. 



B. Head op the Pig. — 1. Occipital bone. — The occipital 

 bone In this animal is not bent anteriorly ; but the transverse 

 protuberance representing the curved lines forms, nevertheless, 

 as in the Horse, the summit of the head. This eminence, which 

 is excavated on both sides on the posterior face, unites in front 

 with the parietal bone, which abuts on the occipital at an 

 acute angle. There is no external occipital protuberance, 

 properly speaking, and the styloid processes are very long and 

 directed downwards. 



•2. Parietal bone. — This bone is very thick, and deprived 

 of an internal protuberance. The process concurring to cir- 

 cumscribe the orbit is short, and joins neither the zygomatic 

 or temporal bones; the orbital arch is completed by a liga- 

 ment. The superciliary foramen, disposed as in the Ox, opens 

 in front into a channel that descends to the nasal bones. The 

 orbital foramen is formed by the frontal bone only. There 

 is no mortice for the union of the frontal with the sphenoid 

 bone, and the maxillary sinus is prolonged into the parietal 

 bone. The frontal bone of the pig articulates with the super- 

 maxilla ries. 



1, Summit of occipital pro- '^- Frontal bone. — The frontal bone of the Pig is very thick 



tuberance ; 2, Parietal and short, and does not join the timporal or zygomatic bone ; 

 bone; 3, Frontal bone, tlie orbital arch is completed by a ligament. The superciliary 

 foramen, disposed as in the Ox, abuts in a channel that 

 descends on the nasal bones. The orbital foramen is formed 

 by the frontal bone only. There is no mortice for the unioa of 



,^ , , -, the frontal with the sphenoid bone ; and the frontal sinuses are 



Zygoma; 6, Lachrymal prolonged into the parietal. The frontal bone of the Pig 

 bone. — B, Lachrymal articulates with the supermaxillaries. 



canals.— 7, Supermax- 4. Sphenoidbone. — The sphenuid of thePig is very short.but 



illary bone.— c. Inferior tlie subsphenoidal processes are extraordinarily developed' and 



orifice of the supei-max- flattened btfore and behind. There is no subsphenoidal canal, 



illo-dental canal; 8, and the sella turcica is deep, and limited behind by a very salient 



Nasal bone ; 9, Pre- crest. A single canal replaces the foramen rotundum and the 



maxillary bone. great sphenoidal fissure, as in the Ox. The wings slightly 



salient, are articulated by suture with the frontal bone. ° 



5 Temporal borie.—The articular surface of this bone resembles that of rodents ; it is 



not hraited posteriorly by a suhcondyloid eminence, and, in addition, offers a wider 



transverse surface. _ The zygomatic process articulates with the jugal bone by the whole 



extent of its posterior border. A crest leading from the external auditory hiatus to the 



HEAD OP THE PIG; 

 ANTERIOR PACE. 



-A, Superciliary fora- 

 men ; a' Channel des- 

 cending from it.- 

 Zygomatic process ; 



