THE TONGUE, BY E. KLEIN. 519 



dalek, junior,* only thirteen times in fifty cases, is continued, 

 by its fundus or posterior wall, which presents a larger or 

 smaller opening directed backwards in the muscular substance 

 of the tongue, into a simple or branched caecal ductus excre- 

 torius linguae, so called because it constitutes the excretory 

 duct common to a large number of mucous glands. 



The epithelium of the foramen caecum is of the ordinary 

 transitional variety ; that of its excretory duct, as well as of its 

 caecal appendix, is cylindrical and ciliated. The foramen caecum, 

 according to Bochdalek, is not formed by an increase in depth 

 of the most posterior papilla circumvallata. 



In regard to the lymphatics of the tongue, Sappey-|- has 

 shown that delicate vessels proceeding from the close lymphatic 

 plexuses of the mucous membrane penetrate into the papillae, 

 and form a superficial network. According to Teichmann, J 

 the lymphatics are confined to the mucosa and submucosa, and 

 form a plexus with coarse deeply situated and more delicate 

 superficial vessels. 



In the papillae filliformes, a few vessels with caecal termina- 

 tions, proceeding from a capillary ring, enter some of the 

 papillae. At the base of the papillae fungiformes, again, a 

 circular plexus of vessels is found, and lymph capillaries are 

 present both in the circumvallate papillae and in the adjoining 

 tissue. 



The muscular fibres of the tongue are vertical, transverse, 

 and longitudinal, the first set belonging to the musculus per- 

 pendicularis at the apex, to the genio-glossus in the middle, and 

 to the lingualis and hyoglossus at the sides. Between these 

 vertically arranged fasciculi run those of the transversus linguae, 

 and in part also of the styloglossus, directed in each half of the 

 tongue from the septum towards the lateral surface. 



Finally, in immediate proximity with the mucous membrane, 



* Bochdalek, junior, Ueber das Foramen Ccecum der Zunge, Oester- 

 reichische Zeitschrift fur Heilkunde, Nos. 36-46. 



t Sappey, Comptes rendus, 1847, p. 26. 



J Teichmann, Das Saugader system vom anatomische Standpuncte. Leip- 

 z'g, 1861, p. 113. 



Salter, Todd's Cyclopedia, p. 1125; and Kolliker, loc. cit., p. 169. 



