354 



ZOOLOGY. 



protruded pharynx, with the posterior zone divided into 

 a number of small areas, each containing two groups of 

 teeth. When the pharynx is withdrawn 

 the external layer becomes the wall of a 

 buccal cavity, with the chitinous teeth 

 projecting inwards : then the teeth serve 

 to prevent the escape of the prey, and to 

 some extent to masticate it. The jaws 

 then lie at the junction of the buccal 

 cavity with the muscular pharynx, and 

 hold and tear the prey. 



6. Posterior End of Body. The seg- 

 ments diminish gradually in size towards 

 the posterior end of the body, and the 

 latter terminates in what is called the 

 anal segment. This bears no parapodia, 

 but the anus is situated at the end of it 

 and is surrounded by a somewhat tumid 

 From the ventral side of this thickening 

 arise two long delicate cirri, called the anal cirri. The 

 terminal segments of the body are represented in Fig. 185. 



Fig. 185. POSTKRIOR 

 END OF BODY OP 

 NKREIS, SHOWING 

 ANAL SEGMENT 

 AND ANAL CIRRI. 



annular border. 



