424 



DIGESTIVE SYSTEM OF THE DOG 



eight to ten curved ridges on either side of the raphe. Behind the first pair of 

 incisor teeth is the triangular incisive papilla, at which the naso-palatine ducts 

 open. The mucous membrane is usually pigmented. 



The soft palate is thick except at its margins. In the resting state of the parts 

 it comes in contact with the oral surface of the epiglottis. Between its anterior 

 and ]iosterior pillars on either side is a marked tonsillar sinus, in which an elongated 

 tonsil is situated; this is reddish in color, about an inch long, and projects somewhat 

 into the fauces between two folds of mucous membrane. 



The tongue is wide, thin, and very mobile. It is not pigmented, but has a 

 bright red color. The upper surface is marked by a median groove (Sulcus medi- 

 anus linguae), and is thickly beset with short, pointed, filiform papillse, the free ends 

 of which are directed backward. On the root the papillae are long and soft; 

 similar papillae occur on the lateral walls of the isthmus faucium. The fungiform 

 papillae are small, and are scattered over the dorsum and sides of the tongue, but 

 are absent on the root. There are usually two or three vallate papillae on either 

 side. Small foliate papillae are also present. In the inferior part of the tip of the 

 tongue is the lyssa, a fusiform cord, composed of fil)rous tissue, muscular tissue, 

 and fat. In large dogs it is about two inches (ca. 4 to 5 cm.) long. 



Fig. 327. — Skull of Adult St. Bkrnard Dog, Sculptured to Show the Embedded Parts of the Teeth. 

 11-3, Incisors; C, canines; Pl-4, premolars; Ml-3, molars. 



THE TEETH 

 The formula for the permanent teeth is: 



(.3 1 4 2 \ 

 I-C-P- M - I 

 3 14 3/ 



