Historical 23 



2. Amphinomorplia. 



Aniphinoiuidae. 



3. Rapacia (Nereimorpha). 



Glyceridae. Syllidae. 



Ncphthyditlae. Phyllodocidae. 



Eunicidae, Sub-faiu. Phyllodocinae. 



Aphroditidae. Alciopinac. 



Stephanidac. Ilydrophaninae. 



Neroidae. Tomopterinae. 



Hesionidae. Appendix: Myzostomidae. 



B.— ACIRRA. 



4. Drilomorpha. 



Cirratulidae. Appendices : Sternaspidae. 



Arenicolidae. Ctenodrilidae. 



Capitcllidae. 



Maldauidae (incl. Ammocharidae). 



5. Terebellomorpha. 



Amphictenidae. 

 Terebellidae. 



6. Serpulimorpha. 



Herniellidae. 

 Serpulidae. 



The above arrangement, with a few slight alterations, was adopted 

 by Profs. Clans and Grobben,^ who, however, did not employ the 

 division into Cirrifera and Acirra, a change for which there is full 

 justification. They divided the Polychaeta directly into six sub- 

 orders, similar in constitution to those defined by Prof. Hatschek, 

 except that the Opheliidae were removed from the Spiomorpha to 

 the Drilomorpha. This classification presents defects, similar to 

 those associated with Prof. Benliam's arrangement, in regard to the 

 great size of the sub-order Eapacia and the heterogeneous contents 

 of the sub-order Drilomorpha. Further, there seems to be little 

 warrant for the inclusion of the Plierusidae (Chlorhaemidae) in the 

 sub-order Spiomorpha. 



Summary. — The systems of classification of the Polychaeta, which 

 have been suggested and have met with acceptance during the last 

 liundred years, may now be summarised and the position of the 

 I'amily Arenicolidae (or Telethusae) indicated in eacli. 



I. Cuvier (1817) distinguished two orders of marine worms — Les 

 Tubicolcs and Les Dorsibranches — by the position of the gills, which 

 in the former are massed at the anterior end, while in the latter they 

 are distributed along the body, as, for instance, in Arenicola. This 



1 Lclu-b. d. Zool., Marburg (1905). 



