128 OUTLINES OF EQUINE ANATOMY. 



The lateral surfaces of the mouth are formed by the cheeks, 

 the mucous membrane lining these presents j^erforated 

 papillse, on which the ducts of the buccal glands pour the 

 secretions of those glands ; varying in position in different 

 subjects, but generally about opposite the space between 

 the second and third molar teeth, we may distinguish the 

 opening of the parotid duct with a larger papilla. The 

 mucous membrane posteriorly is reflected inwards behind 

 the molar teeth to join the posterior pillars of the tongue ; 

 in some places it is coloured by pigmentary deposit. On 

 the roof of the mouth, centrally, it is thick, and presents 

 dense stratified epithelium and a plentiful submucous 

 tissue, in which is situated a remarkable plexus of veins con- 

 gestion of which from dental or other irritation causes that 

 prominence of this part termed "lampas" by individuals 

 who ignorantly considered it a primary diseased condition ; 

 on either side of this runs a palatine artery, as has been 

 described. That portion of the mucous membrane which 

 is attached to the bony palate is termed the hard palate, 

 and inferiorly presents a central groove, from which 

 crescentic prominences, seventeen to eighteen in number 

 on each side, run in an oblique direction outwards. These 

 are termed the "bars," and are straightest and closest 

 posteriorly, where they blend with the 



Soft palate, the mucous membrane of which is redder 

 and less dense, and which runs in a backward direction 

 from the posterior crescentic margin of the x^a^latine bones. 



Occupying the outer circumferent margin of the roof 

 and of the floor of the mouth at particular parts we see the 

 teeth. These are products of mucous membrane. They 

 are hard organs ; by some anatomists considered as bones, 

 but are merely the result of special development of mucous 

 membrane. They are firmly fixed in cavities in bone 

 termed alveolar cavities, and are surrounded by mucous 

 membrane termed the gums. They present three parts : — 

 A fang, th^it part enclosed in the alveolar cavity; crown, 

 that visible on inspection of the mouth after the teeth are 

 fully developed ; neck, that part connecting the fang and 

 the crown, and to which the mucous membrane formmg 

 the gum is attached. Teeth are composed of three sub- 

 stances (two of which closely resemble bone in histo- 

 logical structure), dentine, enamel, and crusta petrosa or 

 cement. They surround a central cavity, which is called 



