258 POLYCHAETA 



BRANCH A. PHANEROCEPHALA. 

 SUB-OEDEH 1. Nereidiformia [ = Errantia, auctt. + Ariciidae\ 



Family 1. Syllidae . see p. 306 Family 8. Amphinomidae see p. 318 



2. Hesionidae . 308 9. Eunicidae . 318 



3. Aphroditidae . 309 10. Glyceridae . 320 



4. Phyllodocidae . 313 11. Sphaerodoridae ., 320 



5. Tomopteridae . 315 12. Ariciidae . 321 



6. Nereidae . 315 ,,13. Typhloscolecidae 321 



7. Nephthydidae 317 



SUB-ORDER 2, Spioniformia. 



Family 1. Spionidae . see p. 321 Family 4. Magelonidae . see p. 325 

 2. Polydoridae . 323 5. Aiumocharidae 325 



3. Chaetopteridae 323 



SUB-ORDER 3. Terebelliformia. 



Family 1. Cirratulidae . see p. 325 Family 3. Ampharetidae see p. 330 

 2. Terebellidae . 327 4. Amphictenidae 330 



SUB-ORDER 4. Capitelliformia. 



Family. Capitellidae, see p. 331. 



SUB-ORDER 5. Scoleciformia. 



Family 1. Opheliidae . see p. 331 Family 4. Scalibregmidae see p. 334 

 2. Maldanidae . 332 5. Chlorhaemidae ,, 334 



3. Arenicolidae . 333 6. Sternaspidae . 335 



BRANCH B. CRYPTOCEPHALA. 

 SUB-ORDER 1. Sabelliformia. 



Family 1. Sabellidae . see p. 336 Family 3. Amphicorinidae see p. 339 

 2. Eriographidae 338 4. Serpulidae . 339 



SUB-ORDER 2. Hermelliformia. 

 Family. Hermellidae, see p. 341. 



Comparative Anatomy of the Polychaeta. 



General Shape of the Body. The majority of the Poly- 

 chaeta have an elongated and very mobile body, like that of 

 Nereis, consisting of an indefinite and usually of a considerable 

 number of segments ; a few, however, have a shorter body, with 

 fewer segments, definite in number, for instance Aphrodite and 

 Polynoe, which have thirty to forty segments ; and some Hesio- 

 nids, with only some seventeen to twenty segments. 



