SEROUS GLANDS OF THE VALLATE PAPILLAE 367 



wall bear glandular outgrowths. The second papilla is simple. 

 Five glands project from the lower border of the epithelial 

 wall, two of which have enlarged ends and slightly constricted 

 necks. The third papilla modeled, that in the foramen caecum 

 (fig. 3) shows many glands at its lower border, some having the 

 same appearance as the two above described. The lateral walls 

 of this papilla also bear gland anlagen resembling in some cases 

 folds of epithelium. 



Nine papillae are present in an 11.5 cm. fetus. One papilla 

 on the left side, near the foramen caecum, was reconstructed. 

 Most of the glands extend downward and slightly caudal ward. 

 Three glands (fig. 4) are longer than the others, the constricted 

 necks having apparently elongated. Gland anlagen are to be 

 found on the outer surface as well as on the lower border of the 

 epithelial wall. 



The tongue in a 12.5 cm. fetus shows twelve papillae. In 

 sections, a very slight furrow is present indicating the site of 

 the developing groove. This groove is only indistinctly indi- 

 cated in a model of the two right anterior papillae. A model 

 of one of these papillae, with its glands, is shown in figure 5. 

 The glands are elongated greatly, their ends are enlarged and 

 the stalks constricted. The stalks and occasionally the bulb- 

 like ends have lumens. The walls of the ducts are formed by 

 two rows of epithelium but the walls of the bulbous ends contain 

 four or five rows. In both of the papillae modeled the greater 

 number of glands are found at the anterior and posterior ends. 

 These glands are longer than those at the sides. Five of the 

 nineteen glands arise from the outer wall, one from the inner, 

 and the remaining thirteen from the lower border of the epithe- 

 hal wall of the papilla. Two of the caudal glands have arisen 

 so close to each other that they give the appearance of branches 

 from a single outgrowth. The larger of these glands divides 

 almost immediately, one branch extending caudalward almost 

 in a horizontal plane, the other extending downward and caudal- 

 ward for a short distance, then again dividing. At the pomt 

 of the latter division, the duct is somewhat enlarged and has a 

 well-defined lumen. The two subdivisions project straight 



