INTRODUCTION. 



XIX 



is forced down into the tube, and brought well within the 

 range of its peristaltic movements. The upper extremity 

 of the oesophagus is frequently organized as a distinct 

 pharynx (Woodcut, fig. vi. ph}, a wide, funnel-shaped 



Fig. yi. 



i- 



Polypide o/Bugula plumosa. 



pk. Pharynx, oe. (Esophagus, c. Cardia. cc. Cardiac cavity, st. Stomach, 

 en. Caccal appendage, t. Intestine, p. Pylorus, a. Anus. /. Funiculus. 



chamber, with muscular walls, capable of vigorous con- 

 tractions, within which the particles of food collect, and 

 from which they are hurled down the oesophageal tube at 

 intervals into the stomach. 



The surface of the pharynx appears to be dotted over 

 with minute spots (Woodcut, fig. vi. ph) ; down one side 

 of it runs (in many cases, if not universally) a band, which 

 is crossed by transverse striae, and which is very conspi- 

 cuous from the contrast it presents to the rest of the 

 structure. It also attracts attention from its vigorous 

 movements, which are connected with the expansion and 

 contraction of the pharynx. There can be no doubt that 



c2 



