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THE BONES. 



which forms part of the sphenoid sinus. The posterior border presents, above, 

 a rugged crest called the palatine, flattened from side to side, bent outwards, and 

 bordered at its base and inwards by a very narrow synarthrodia! surface, which 

 responds to the pterygoid bone. It is smooth and concave in its inferior half, 

 and forms, with that of the opposite side, a parabolic arch (palatine arch) which 

 circumscribes, below and at the side, the double guttural orifice of the nasal 

 cavities. 



Extremities. — The superior, flattened on both sides, is bevelled on the external 

 side to articulate with the subspheuoidal process. The 

 inferior, flattened from before to behind, is curved 

 inwards and united by simple suture with that of the 

 opposite bone. 



Structure and development. — This is a very com- 

 pact bone, developed from a single centre of ossifi- 

 cation. 



Differential Characters in the Palatine Bone in 

 OTHER Animals. 



The principal distinctive feature of this bone in the different 

 domestic animals is due to the part it takes in forming the 

 arch of the palate. In tliis respect there are very great differ- 

 ences in vaiious species, but in none of tliem is this part so 

 redufcd as in Solipeds, in which the bone is scarcely equal to 

 one-fifth of the palatine surface. 



A. Ox, Sheep, Goat. — 'I'l.e palatine bone in these animals 

 is very developed, and noticeable for the considerable extent of 

 the palatine portion of its external surface. The palatine canal 

 is entirely channeled uut in its substance. The palatine cri 8t, 

 very thin an I elevated, is formed altogether by the posterior 

 border of the palate bone, the pterygoid, and the subsphenoidal 

 process. There is no excavation for the sphenoidal sinuses ; 

 but, instead, all that part of the bone which enters into the roof 

 of tlie palate is hollowed, but in the Ox only, by irregular 

 cavities which communicate with the maxillary sinus of the 

 same side. The nasal foramen is very wide. 



B. Camel. — The btaphyline fissure is wide and deep; the 

 palatine crest is very developed, and has two rugged depressions 

 at its base. The palatine canal is not included in the palate 

 bone ; it opens at the second molar. 



C. Pig. — The palatine portion is less developed than in 

 Ruminants, for it forms less tlan one-fourth of the palatine 

 arch ; on the other hand, the orbital portion is very limited. 

 Tiie palatine crest is n placed by a tuberosity, against which 

 rests, outwardly, the subsphenoidal process, and inwardly the 

 pterygoid bone. Tlie union of these three parts constitutes, on 

 the posterior surface of tlie head, a thick and very remarkalde 

 trifid projection or mamelon. 



D. Dog, Cat.— It is in the C;rnivora that tlie palatine bones 

 are of greatest extent in their proper palatine jiortion, as they 

 constitute nearly one-half of tlie palatine arcli. They have no 

 share in the formation of the sphenoidal sinuses, but furnish a 

 small excavation to the maxillary sinuses. 



E. Rabbit. — The palatine bones lesemble those of the Horse, 



dog's head (posterior face). 



1, Occipital tuberosity ; 2, 

 occipital foramen ; 3, occi- 

 pital condyle ; 4, condyloid 

 foramen ; 5, styloid process 

 of the occipit;il ; 6, mastoid 

 protuberance ; 7, concave 

 temporo-maxillary articular 

 surface ; 8, supra-condy- 

 loid eminence; 9, inferior 

 orifice of the parietu-tem- 

 poral canal ; 10, posteridr 

 foramen lacerum ; 11, 

 ditto, anterior. On the op- 

 posite side at a is shown 

 the orifice communicating 

 with the Eustachian tube 

 and the tympanum ; at b 

 the passage for the carotid 

 loop. 12, Body of the 

 sphenoid ; 13, oval fora- 

 men ; 14-, inferior orifice of 

 the subsphenoidal canal ; 

 15, pterygoid bone ; 16, 

 nasal surface of the palate 

 bone; 17, palatine surface 

 of the same; 18, vomer; 



19, supermaxillary bone ; 



20, incisive opening. 



with regard to the part they play in forming the palatine arch. 

 The palatine canal opens also between the palatine and superior 

 maxillary bones, but the palatine crests are proportionately 

 more developed than in Solipeds (Fig. 35). 



