ORGANS OF THE SENSES. 497 



parison of these papillae to a cylinder is rendered almost com- 

 plete. (See Plate LXIY. fig. 3.) 



We shall presently see that the same circular arrangement 

 extends to the filiform epithelial appendages hereafter to be 

 described, and one of which corresponds to each secondary 

 papilla.* 



The fungiform papilla are seated principally on the tip 

 and sides of the tongue, at least they are most evident in 

 those situations, and around each a space or shallow fossa, 

 dotted with numerous simple papillae, may be observed ; they 

 are distinguished from the filiform papillae by which they are 

 surrounded, by their form, being narrow at the base, and di- 

 lated near the summit, by being clothed all over with simple 

 papillae, which are usually a good deal compressed in form, 

 and by the tenuity of the epithelium, destitute of filiform 

 appendages, which covers them, and which allows of the 

 blood in the vessels being seen through it. (See Plate 

 LXIY. fig. 5.) 



At the edges of the tongue, and at the sides behind the 

 calyciform papillae, compound papillae exist, which bear some 

 resemblance to the fungiform papillae, of which they may be 

 described as modifications; they differ from ordinary fungi- 

 form papillae, however, in being sessile and simply rounded; in 

 the form of the simple papillae which clothes them, and which 

 usually are not compressed, but swollen at the extremity, or 

 pyriform. (See Plate LXY. fig. 11.) 



The calyciform papillae bound the true gustatory region 

 posteriorly ; they are seven or eight in number, and arranged 

 in two rows, which meet behind in 'the foramen caecum, and 

 enclose a Y-shaped space, the concavity of which looks for- 

 ward. 



They each consist of a depression or cup, out of which a 

 large papilla, sometimes more or less adherent to the rim of 

 the cup, arises, and the fevel of which it but little exceeds; 

 the central papilla, as well as the sides and margin of the 



* The form and structure of the filiform papillae, as above detailed, was 

 first described by me in the Lancet of 3rd March, 1 849. 



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