APPENDIX TO CHAPTER 



159 



APPENDIX TO CHAPTEPv X 



KEY TO THE MORE IMPORTANT FAMILIES OF POLYCH.^TA 



a\. Head distinct from trunk ; proboscis protrusible 



[wandering Polychseta]. 

 bi. With broad dorsal scales .... 



b-2. No scales ; only one mouth-segment. 



Ci. Cirri not leaf-like ; body long and not 



flattened. 

 d\. Head not segmented. 



e\. Jaws composed of many pieces . 

 e-2- Two powerful jaws . 



d. Head with its lobes segmented . 



c 2 . Small worms, body flattened, cirri evident 



o. Head not distinctly separated from trunk ; pro- 

 boscis short, not protrusible ; no jaws [seden- 

 tary Polychseta]. 

 bi. Gills, when present, arise either from almost 



all, or else the middle segments. 

 GI. Body not separated into various regions ; 

 distinct head ; no antenna ; gills in 

 form of elongated, thread-like cirri 



C 2 . Body divided into 2 or 3 different regions ; 

 no antennal cirri ; proboscis present ; 

 no gills 



& 2 - Gills almost always present and limited to the 



anterior end of the body ; no cirri ; body 



divided into an anterior and a posterior part. 



Ci. Gills confined to the anterior segments ; 



head lobe small ; numerous antenna in 



2 bunches ; no antennal cirri 



c 2 . Gills confined to head ; 2 inrolled leaves 

 standing at the sides of the mouth 



Aphroditidce 



(Ex. Lepidonotus) 



Eunicidce 



Nereidu' 



(Ex. Nerds) 



Glycerida* 



(Ex. Ki 



(Ex. Antolytus) 



Cirratulidce 



(Ex. C'irratulus) 



Maldanidaz 



(Ex. ClymeiH'llu) 



Terebellidce 

 (Ex. Amphitrite) 



SerpulidoK 



(Ex. Serpula) 



