456 SPECIAL HISTOLOGY. 



hardly pass beyond its middle anteriorly, while on the other hand, those 

 of the soft palate form a considerable layer of glands upon its under 

 side, which anteriorly measures as much as 3-4 lines, diminishing, how- 

 ever, somewhat towards the free edge and the uvula. On the posterior 

 surface of the soft palate, also, glands exist, but they are much smaller, 

 and do not always form a connected layer. 



4. The lingual glands, among which I distinguish : — 



a. The mucous glands of the root of the tongue. — These form a stra- 

 tum, in parts very thick, of glands |^-2 lines in diameter, beneath the 

 simple mucous sacs of the root of the tongue, to which we shall have to 

 refer hereafter, and the pajnllce circumvallatce ; it presents, especially 

 beneath the former, a thickness of as much as 4 lines, and extends almost 

 continuously from one tonsil to the other. In front of the foramen 

 ccecum 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 

 pajjillce 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 lines long in the posterior glands, and open, as E. H. Weber first 

 showed, by a funnel-shaped expansion into the simple mucous sacs of 

 the root ; in the neighborhood of the papillce circumvallatce, on the other 

 hand, they open independently between the lingual papillse, and into the 

 clefts which surround the circumvallate papillae, a few also on the walls 

 of the foramen ccecum. 



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 jjapillce 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 hgo-glossus 

 and transversus. In animals, these glands, as well as the folds'(Mayer's 

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



c. The glands of the jJoint 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 lines long, 2-3 lines thick, 3-4 lines broad, where 5 or 

 6 excretory ducts open upon peculiar lobed folds of mucous membrane 

 close to the frenulum linguce ; 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 organization and inva- 

 riably consist of a certain number of glandular lobes with a branched 



