FOOD AND DIGESTION. 



349 



the papillae. The nerves in the fungiforin and circumvallate papillse 

 form a kind of plexus, spreading out brushwise (fig. 244), but the exact 

 mode of termination of the nerve-filaments is not certainly known. 



In the circumvallate papillae of the tongue of man peculiar struc- 

 tures known as gustatory buds or taste goblets, have been discovered. 

 They are of an oval shape, and consist of a number of closely packed, 



very narrow and fusiform, cells 

 (gustatory cells}. This central 

 core of gustatory cells is in- 

 closed in a single layer of 

 broader fusiform cells (incas- 

 ing cells). The gustatory cells 

 terminate in fine spikes not 

 unlike cilia, which project on 

 the free surface (fig. 245 a). 



These bodies also occur side 

 by side in considerable num- 



e 



/ f . Fig. 244. Fig. 245. 



Fig. 244. Two filiform papillae, one with epithelium, the other without. &j*-. d, the substance of 

 the papillae dividing at their upper extremities into secondary papillae ; a, artery, and v, vein, 

 dividing into capillary loops ; e, epithelial covering, laminated between the papillae, but extended 

 into hair-like processes, /, from the extremities of the secondary papillae. (From Kolliker, after 

 Todd and Bowman.) 



Fig. 245 Taste-goblet from dog's epiglottis (laryngeal surface near the base), precisely similar 

 in structure to those found in the tongue, a, depression in epithelium over goblet; below the letter 

 are seen the fine hair-like processes in which the cells terminate ; c, two nuclei of the axial (gusta- 

 tory) cells. The more superficial nuclei belong to the superficial (incasing) cells ; the converging 

 lines indicate the fusiform shape of the incasing cells. X 400. (Schofleld.) 



bers in the epithelium of the papilla foliata, which is situated near the 

 root of the tongue in the rabbit, and also in man. Similar taste-goblets 

 have been observed on the posterior (laryngeal) surface of the epiglottis. 



THE PHAKYNX. 



The portion of the alimentary canal which intervenes between the 

 mouth and the oesophagus is termed the Pharynx. It will suffice here 

 to mention that it is constructed of a series of three muscles with stri- 



