THE TONGUE. 311 



zontal, while the posterior makes a somewhat vertical 

 bend down to the os-hyoides. This account of its direction 

 is true when the tongue is kept within the mouth, hut 

 when it is protruded, the os-hyoides rises, and the whole is 

 then on nearly the same horizontal level. 



The form of the tongue is somewhat of an ellipse. Its 

 upper surface or dorsum presents a very rough aspect from 

 numerous eminences called papillae, (papilla, a nipple.) 

 These papilla? are various in size, and have received dif- 

 ferent names. Those at the hase, arranged in the shape 

 of the letter V, are the papillce maximce. (Fig. 89.) They 

 are ahout nine in numher, though as many as sixteen and 

 twenty are mentioned. They are the largest in size, and 

 present two rows, forming at their point of union a hlind 

 opening called the foramen ccecum of Morgagni, regarded as 

 the receptacle of mucous secretion from the follicles. These 

 papillae maximae resemble a cone, have their base above 

 and free, while the apex is below and fixed in a cup-like 

 cavity, whence they are also called calyciformes. Within 

 this cup a fossa, or circular trench, is seen surrounding 

 the papilla, from which also the name of circumvallatce, 

 is derived. 



The papillce mediae, or fungiformes, the next in size, 

 are found irregularly scattered over the dorsum of the 

 tongue, and some are seen at the tip. They are easily re- 

 cognized by the rounded and flattened tops resting on a 

 narrow pedicle, and having a direction backwards. 



The papilla! villosce or conical, and the filiform, are the 

 smallest and most numerous; they cover the whole surface 

 of the tongue, being scattered among all the others, and 

 are most abundant at the tip. 



Blood-vessels of papillae. The microscope of Mr. Nasmyth 

 discovers the elements of the papillae to consist of capillary 

 vessels and loops of terminal nervous filaments, connected by 

 an areolo-fibrous tissue. The capillaries are found to pro- 

 ceed from a small artery running through the centre of the 

 papillae, (Fig. 90, B,) and then ending in a vein which re- 

 turns along the course of the artery. A variety is observed 



