THE CAT 235 



The soft palate is the soft flap forming the hinder portion 

 of the roof of the mouth ; it will be seen to be much narrower 

 than the hard palate. The narrow space forming the hinder part 

 of the mouth cavity, bounded dorsally by the soft palate and ven- 

 trally by the root of the tongue, is called the isthmus faucium. 

 Diverging from each side of the soft palate to the side of the 

 tongue and the ventral wall of the pharynx are two folds called 

 the anterior and posterior pillars of the fauces. From each of 

 the lateral sides of the isthmus between these pillars a prominent 

 lobed gland called the tonsil projects into the cavity. 



The floor of the mouth is formed principally by the tongue, 

 which is a muscular organ projecting from it. The free end of 

 the tongue is joined with the floor of the mouth by means of a 

 median fold called the frenulum linguae. 



The upper surface of the tongue is provided with three kinds of 

 papillae, — the filiform, fungiform, and circumvallate. The filiform 

 papillae cover the upper surface, those on the middle and forward 

 portions having the sharp, horny tips which form the rasping sur- 

 face peculiar to carnivorous mammals ; the fungiform papillae are 

 enlarged at their free ends, and are the prominent projections in 

 the middle and at the sides of the tongue near its root, those at 

 the sides being very large ; the circumvallate papillae are promi- 

 nent projections, each surrounded by a circular groove and a 

 ridge, which are present in two rows of two or three papillae 

 each, at the posterior part of the tongue, between the lateral 

 fungiform papillae. 



The pharynx lies just back of the soft palate. Two passages 

 open into it at its anterior end and two at its posterior end. The 

 two anterior passages are the isthmus faucium, the hinder end of 

 the mouth, and the nasopharynx. This latter space is a part of the 

 respiratory passage. It lies immediately above the soft palate 

 and the hinder part of the hard palate, and communicates poste- 

 riorly with the pharynx and anteriorly with the nasal cavities. 

 Probe it and determine its extent. 



The two posterior openings of the pharynx are the oesophagus 

 and the glottis. The latter is the opening into the larynx and is 

 ventral to the oesophagus; it is guarded by the epiglottis, a tri- 



