242 VERTEBRATES. 



foliata), which is crossed by minute, oblique, parallel lines. 

 There are some relatively large taste buds imbedded in 

 this part. Between the two oval areas of opposite sides, 

 and a little farther back, there are four large papillae 

 (circumv allate papillae) arranged in a posteriorly convex 

 curve, two on either side of the median line. Each of 

 these papillae is surrounded by a circular groove. 



III. The Palate and Adjacent Parts. Study the palate. 

 It is the narrow, median strip or area along the roof of the 

 mouth. Its anterior portion, which is raised into trans- 

 verse ridges against which the tongue rubs, is called the 

 hard palate. Its smooth, soft, posterior half is called the 

 soft palate. It ends behind in a free border. 



Just behind the small upper incisors are a pair of 

 minute pores opening into small canals which extend up- 

 ward, connecting the cavities of the nose and the mouth. 



A pair of small pits at the sides of the soft palate, near 

 its hinder border, are the tonsils. 



The pharynx is the backward continuation of the mouth 

 beyond the soft palate. The nasal chamber opens into it 

 above the soft palate. 



The JEustachian tubes, coming from the ear, open on the 

 sides of the posterior nasal chamber within, about the 

 middle of the soft palate. Split the soft palate longi- 

 tudinally, turn apart the severed edges, and find the two 

 openings. 



IV. The Salivary Glands. Find the salivary glands. 

 They are four pairs of large, pinkish, reddish, or whitish, 

 lobulate bodies which secrete saliva, and pour it into the 

 mouth through small salivary ducts : 



1. The parotid gland is the largest. It lies in front of, 

 and just below, the external auditory canal. Its duct 

 runs forward at first, just beneath the skin, and opens on 

 the inside of the cheek, opposite the second upper molar 

 tooth. 



