GLANDS OF THE ORAL CAVITY. 25 



which we shall have to refer hereafter, and the papilla circum- 

 vallatce; it presents, especially beneath the former, a thickness of 

 as much as 4'", and extends almost continuously from one tonsil 

 to the other. In front of the foramen caecum these glands are 

 smaller and more scattered, but a few occur more or less deep in 

 the muscular substance in front of the most anterior papillae 

 circumvallatce ; they are never found, however, further forwards 

 than the middle of the tongue. 



The excretory ducts of the glands, which are interwoven 

 with the extremities of the genio-glossus and partly united 

 with them, are as much as 6'" long in the posterior glands, and 

 open, as E. H. Weber first showed, by a funnel-shaped ex- 

 pansion into the simple mucous sacs of the root ; in the 

 neighbourhood of the papillae circumvallatce, on the other hand, 

 they open independently between the lingual papillae, and into 

 the clefts which surround the circumvallate papillse, a few also 

 on the walls of the foramen caecum. 



b. The marginal glands of the root of the tongue. — At the 

 borders of the root of the tongue we find, at the level of the 

 papillae circumvallatce many perpendicular laminated folds, to 

 which reference has already been made and between them fine 

 apertures, which belong to a special small group of glands lying 

 in the midst of the expansion of the hyo-glossus and transversus. 

 In animals, these glands, as well as the folds (Mayer's organ), 

 are often very greatly developed. (See Briihl, 1. c.) 



c. The glands of the point of the tongue. — On the lower 

 surface of the apex of the tongue, but still in the substance of 

 the lingualis inferior and stylo-glossus, there lie, right and left, 

 two elongated broad glandular masses 6 — 10'" long, 2 — 3'" 

 thick, 3 — 4'" broad, where 5 or 6 excretory ducts open upon 

 peculiar lobed folds of mucous membrane close to the fraenulum 

 linguae ; these glands were long ago accurately described by 

 Blandin, and have been recently rescued from oblivion by 

 Nuhn. 



§ 134. 



Intimate structure of the mucous glands. — All these glands 

 agree in the essential characters of their intimate organisation 

 and invariably consist of a certain number of glandular lobes 

 with a branched excretory duct. The lobes, of which in the 



