312 



THE TONGUE. 



in the capillaries of the different papillae in those of the 

 conical papillae of the foetus a coarse net-work is observed, 

 and a vascular ring surrounding the apex of each papilla, 

 giving the appearance of an aperture. In the filiform 

 papillae, the capillaries are seen as a single loop, (Fig. 90, 

 A,) while in the papillae maximae or calyciformes, (Fig. 

 90, A ? ) they are more tortuous and of the plexus form. 



Behind the papillae maximae some eminences are ob- 

 served having the same arrangement as these papillae. They 



A FIG. 90. 



were formerly 

 considered 

 among the pa- 

 pilla3, but are 



now regarded as glands. They have perforations which 

 are visible to the eye, and being found to have the same 

 structure as the parotid, are considered salivary and not 

 mucous glands. 



The upper surface of the tongue has beneath its mucous 

 coat a dense membrane, which resembles the corium of the 

 skin, and is called the papillary membrane from its giving 

 support to the papillae. In some instances it is almost as 

 hard as cartilage. It is divided along the median line by a 



FIG. 90, A represents the Papillae on a part of the surface of the Tongue of 

 an adult, and shows the manner in which the vessels are distributed. Pa- 

 pilloe maximae or calyciforme. 6 6 The groove around it. c Papillae filiformes, 

 or thread-like papill. d Conical papillae. 



FIG. 90, B represents a conical Papilla, having at its extremity a An aperture* 

 The distribution of its vessels is also seen. 



