172 THE CAT. [CHAP. vi. 



Its function is unknown, but it is supposed to help the tongue in its 

 lapping action. 



The mucous membrane, which invests the tongue, forms a fold 

 beneath it and in front (attaching it to the lower jaw) termed the 

 frcenum linguce, and thence it is continued onwards (over the muscles 

 forming the soft floor of the mouth) till it reaches the gums. A 

 minute process the salivary papilla projects forwards on each 

 side of the framum. 



The upper surface of the tongue is flat, with a depressed area 

 behind, which is bounded posteriorly by the epiglottis or cartilage 

 guarding the entrance to the windpipe. 



The surface of the tongue is smooth beneath, but above it is beset 

 with papilla? of four kinds: 



(1.) The first are the circumvallate papillce, each of which consists 

 of a flattened prominence (shaped like a truncated, inverted 

 cone), with a sort of trench round it. A few of these are dis- 

 posed in two rows converging posteriorly like a widely open 

 letter Y (Fig. 87, cv). 



(2.) The fungiform papilla are much smaller and more numerous 

 than the circumvallate ones. Each is somewhat swollen and 

 rounded at its tip, while it is smaller at its point of attach- 

 ment. These papillaB (/) are found especially at the sides of 

 the anterior part of the tongue. 



(3.) The conical papillae are very numerous and closely set over 

 the dorsum of the tongue, with their apices directed back- 

 wards. They are small and simple near the edges and tip of 

 the tongue, but over the greater part of the dorsal surface they 

 are much larger and horny in consistency like so many 

 minute claws especially towards the middle line. It is the 

 presence of these horny papilla which makes the cat's tongue 

 so rough and rasp-like. 



(4.) The flattened papillae are a group of very large, soft, flattened 

 and pointed papilla, placed behind the circumvallate papillae 

 on the dorsum of the root of the tongue. 



10. Besides the secretion of the small mucous glands, the 

 cavity of the mouth is moistened by the product of various kinds of 



SALIVARY GLANDS. 



The first of these, the parotid, is a branching, or racemose,* gland, 

 consisting of many lobes held together by their excretory tubules, 

 blood-vessels, and areolar tissue, and lined throughout with epithelium. 

 It forms a crescentic mass, with its concavity applied to the under 

 and anterior aspect of the cartilage at the root of the external ear, its 

 lower border being prolonged downwards and forwards (Fig. 88, p). 

 Its duct (called Steno's or Stenson's) runs forwards across the mas- 

 seter muscle, and perforating the buccinator, opens inside the cheek 

 opposite the sectonal teeth. Two small separate accessory portions 



'- For a description of the different varieties of glands, see 8, in the 

 chapter on the Organs of Respiration and Secretion. 



