71 



or larger groups, in the submucous tissue, and are frequently in con- 

 tact with the bundles of muscular fibres. 



With the single exception of the tongue just mentioned, all my 

 specimens had quite well developed foliate areas, as well developed in 

 foet, as in many rodents whose tongues I have examined. 



Description of the Papilla foliata. — This papilla consists of 4 or 5 

 rather irregular folds, with slightly rounded crests, separated by fur- 

 rows, which vary much in breadth, and slightly in depth. The usual depth 

 is about 1,5 mm. Occasionally the bottom of a furrow is invaginated 

 upwards into a ridge, which may or may not bear taste bulbs. Serous 

 glands and ducts are very abundant at the base of the folds and also 

 occupy a large space within them. Some of the ducts of these glands 

 are very long and tortuous, and measure several millimetres in length. 

 They usually open between the folds at the bottom of the furrows. 

 I have seen in vertical sections as many as five separate ducts opening 

 at the base of a single furrow ' ). Glands of the mucous type are 

 also sparingly scattered through this region. Each fold carries at its 

 upper part many secondary papillae, the depressions between which 

 are filled by the epithelium. 



The taste bulbs of this gustatory region are a little smaller on 

 the average than those of the circumvallate area. Their length is 

 about 0,066 mm, and their greatest breadth 0,039 mm. They are 

 placed at the sides of the folds, sixteen tiers deep, the uppermost tier 

 being sometimes on a level with the free opening of the furrow. 

 Occasionally they are present only upon one side of the furrow, and 

 more rarely both sides are destitute of them. From horizontal and 

 vertical sections I estimated the number of bulbs in each papilla 

 at 2400. 



There is a lack of uniformity in the shape of the bulbs. Some 

 of them resemble those of the rabbit, being flask-shaped bodies, with 

 a slender neck, at first slightly constricted, but as it nears the free 

 surface of the epithelium gradually broadening out and attaining its 

 greatest diameter at the pore. In these bulbs the neck measures 

 0,006 mm in length , and the diameter of the taste-pore is about 

 0,003 mm. Through the latter the peripheral processes of the gusta- 

 tory cells can be seen protruding a short distance. In many bulbs, 

 however, the neck is short and the opening on the exposed surface 

 narrow. 



1)1 have observed the same number of serous ducts opening at the 

 base of a furrow in the gustatory lamellae of the human infant, where 

 the sides and upper surface of the folds are crowded with bulbs. 



