KEY FOR IDENTIFICATION FROM TUBES 461 



77 (76) The length of the segments is equal to or more than the diameter 



of the tube, which is 1 -5 mm. Lamellisabella ivanovi (p. 434). 



78 (75) The tube is devoid of segments or segmentation occurs only at the 



hind end. 



79 (80) The tube is transparent. The front and back sections are brownish 



and firm. The middle section is thin-walled, flexible and straw- 

 coloured. The diameter is not more than 1 -4 mm. 



Spirobrachia beklemischevi (p. 450). 



80 (79) The tube is opaque, stout-walled, more or less the same all along 



its length and dirty brown or black. 



81 (82) The diameter of the tube is up to 2 mm. 



Lamellisabella zachsi (p. 423). 



82 (81) The diameter of the tube reaches 2-8 mm. 



Spirobrachia grandis (p. 446). 



