460 PART II. SYSTEMATIC ACCOUNT 



61 (62) The tube is up to 0-12 mm in diameter. The stoutish rings are 



brownish with reddish tints. Siboglinum minutum (p. 248). 



62 (61) The diameter of the tube lies between 0-2-04 mm. 



63 (61) The rings vary greatly in length. Generally in the front half of the 



tube, side by side with exceedingly short rings are found some 

 which are several times as long as the diameter of the tube. Nearer 

 the hind end of the tube the rings become more or less regular and 

 not longer than the diameter of the tube, while the edges of some of 

 them seem eroded. The diameter of the tube is up to 0-25 mm. 



Heptabrachia gracilis (p. 338). 



64 (63) The rings are all more or less equal in length, and become very 



irregularly shaped in the hind part of the tube, whose diameter may 

 reach 0-33 mm. Heptabrachia abyssicola (p. 335). 



65 (6) The tube is not ringed; if there are any rings present they are only 



in the very hindmost part. 



66 (67) The tube is white and elastic, and only the hindmost part may be 



dirty brown or blackish. It is segmented, and between the segments 

 are narrow clear intervals. The diameter may be up to 1 -6 mm and 

 the length as much as 1 -5 mm. Zenkevitchiana longissima (p. 388). 



67 (66) The tube is dirty brown or black, firm and unbendable. 



68 (69) There is no obvious segmentation. The diameter is about 1 mm. 



Cyclobrachia auriculata (p. 367). 



69 (68) The tube is clearly segmented. The front edge of each segment has 



a filmy border forming a sort of funnel (sometimes not preserved). 



70 (73) The diameter of the tube is not more than 1 -2 mm. The surface of 



the tube is devoid of any felt-like layer. 



71 (72) In the front part of the tube the funnel-shaped borders of the 



segments are placed very close to one another, looking almost like 

 a pile of saucers. The diameter of the tube is 0-5 mm. 



Polybrachia gorbunovi (p. 400). 



72 (71) In the front part of the tube the funnel-shaped borders of the 



segments are rather far apart. Polybrachia annulata (p. 394). 



73 (70) The diameter of the tube is about 2 mm. The surface of the tube is 



covered with a felt-like layer. The funnels occur at frequent 

 intervals. Galathealinum bruuni (p. 404). 



74 (1) The front end of the tube is firm, with a funnel-shaped mouth. 



75 (78) The tube is segmented. 



76 (77) The length of the segments is rather less than the diameter of the 



tube, which is about 1 -7 mm. Lamellisabella johanssoni (p. 429). 



