THE TEETH 
493 
posterior pillars on either side is a marked tonsillar sinus, in which an elongated, 
fusiform tonsil is situated; this is reddish in color, 
about an inch long, and is largely or completely 
concealed between two folds of mucous membrane. 
The posterior pillar is double; the upper fold passes 
to the dorsal wall of the pharynx, where it subsides; 
the lower fold goes to the side of tke epiglottis. 
The tongue is wide and thin in front, thicker 
posteriorly; itis very mobile. It is not pigmented, 
but has a bright red color. The dorsum is marked 
by a median groove (Sulcus medianus linguz), and 
is thickly beset with short, pointed, filiform papille, 
the free ends of which are directed backward. On 
the root there are long conical papille which are 
soft, and point backward; similar papille occur 
on the lateral walls of the isthmus faucium. The 
fungiform papill are small, and are scattered over 
the dorsum and sides of the tongue, but are absent 
on the posterior part of the dorsum and on the 
root, where the conical papille occur. There are 
usually two or three vallate papillz on either side 
on the posterior part of the dorsum, where the 
conical papille begin. Small foliate papille are 
also present just in front of the anterior pillars of 
the soft palate; they are oval and are crossed by 
about half a dozen fine fissures. In the inferior 
part of the tip of the tongue is the lyssa, a fusiform 
cord, composed of fibrous tissue, muscular tissue, 
and fat. In large dogs it is about two inches (ca. 
4 to 5 em.) long. The lingual muscles present no 
remarkable special characters. 
THE TEETH 
The formula of the permanent teeth is: 
Se OE: Sa 
2{ I-C—P—-M-— } = 422 
3 4 3 
All of the teeth have short crowns and dis- 
tinct necks; they erupt rapidly. The crowns are 
white, being destitute of cement.! 
The incisors are placed almost vertically and 
close together in the jaw bones. They do not cor- 
respond to an opposing tooth, but rather to parts 
of two teeth of the other jaw. They increase in 
size from the first to the third. The crowns are 
trituberculate, the central projection being the 
largest. The labial surface is convex; the lingual 
surface is slightly concave, and is marked off from 
the neck by a V-shaped ridge, the cmgulum. The 
roots are narrow transversely. The lower incisors 
are smaller than the upper ones. 
Fic. 434.—Toneve, PHarynx, Larynx, 
ETc., OF Doc; Dorsat VIEW. 
The pharynx and soft palate have 
been cut medially and reflected, and the 
cesophagus cut off. 
1, Median groove of tongue; 2, long 
conical papille of root of tongue; 3, val- 
late papille; 4, tonsil (drawn out of ton- 
sillar sinus; 5, floor of pharynx (promi- 
nence here caused by cricoid cartilage 
and m. crico-arytenoideus dorsalis); 7, 
vestibule of larynx; 8, epiglottis; 9, ary- 
tenoid cartilage; 10, trachea (membran- 
ous part); 11, 11, lateral lobes of thyroid 
gland; 12, 12’, anterior and posterior thy- 
roid vessels. 
One or two supernumerary teeth may be present. 
The canine teeth are large, conical, and curved. The upper canine is separated 
1 Other figures which illustrate the teeth are to be found in the description of the skull. 
