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SABELLIDAE. 



(1) Dorsal bristles on the thorax of one kind 



(einerlei Art) . . . ,. . . Sabella. 



(2) Dorsal bristles on the thorax of two kinds . Potamilla. 

 b. Without a collar Amphiglena, 



II. Tori on the thorax have no double rows. 



a. Uncini on the abdomen as in Sabella. 



a. Thoracic hooks elongated . . . . . . Jasmineira. 



b. Hooks on the thorax short. 



a. Branchiae with dorsal appendages .... Dasychone. 

 (3. Branchiae without dorsal appendages .... Laonome. 

 y. Branchiae spiral ....... Bispira. 



b. Abdominal hooks as in Serpula and Terebella. 



a. Branchiae with a web. 



«. Without a collar. 



(1) Thorax without uncini . . . . . Myxicola. 1 



(2) Thorax with uncini . . . . . . Leptochone. 



/3. With a collar. 



(1) No anal groove Ghone. 



(2) Anal groove .... . . . Euchone. 



b. Branchiae without a web. 



a. Branchial filaments do not end in a process . . Dialychone. 

 /3. Branchial filaments end in a process. 



(1) With a collar . . . . , . . Oria. 



(2) Without a collar ...... Fabricia. 



Levinsen 2 (1883) chose the old method of grouping the Sabellidae and Serpulidae 



together under his title Sabelliformia. The arrangement of his genera was : — Amphicora, 

 Notaulax, Euchone, Ghone, Laonome, Dasychone, Sabella, Potamilla. 



De St. Joseph (1894) followed Claparede and others in grouping the Sabellidae 

 under the Serpulidae and uniting with them the Eriographididae and the Amphicoridae. 

 The presence or absence of a thoracic membrane did not appear of sufficient importance 

 to separate the groups. Accordingly he ranged all in a single family — Serpulidae — under 

 which he made two tribes, viz., (1) Sabellidae, in which the tube is formed of mucin e and 

 coated with debris of shells and sand, and either free or sunk in the sand. No thoracic 

 membrane and no operculum. 



(2) Serpulidae : Tube of mucine combined with calcareous matter, or rarely with 

 a crystalline translucent substance like chalcedony. Generally a thoracic membrane and 

 an operculum. 



He classifies the Sabellidae mainly according to the arrangement of the hooks and 

 bristles, taking the nature of the collar and the branchiae also into account. 

 I. Thoracic hooks avicular with oar-shaped bristles. 



I a. A single row x of avicular hooks on the abdominal processes. 



1. With a collar. 



1 This is inaccurate as regards the common species. 

 3 Op cil, p. 180. 



