252 Mr. J. W. Pryde on Annelida Polychata 



The tubes differ very much in size and thickness, and 

 wliile some have rings clear, well mnrked, and at regular 

 intervals, others have them irregularly placed and almost 

 indistinct. The tubes found at Buchan Deep are about 

 8 inches long, fairly thin, clear, and nearly transparent, and 

 are almost entirely filled with very fine sand. They have 

 irregularly arranged transverse striations, and at one end 

 there is often a perforated septum, which probably acts as a 

 means of defence and at the same time functioning as the 

 V-shaped or zigzag valves in Hyalinoecia tuhicola. Prof. 

 M'Intosh, in his remarks on this genus in the 'Challenger' 

 collection, says : — " Toward the posterior end a very neat 

 diaphragm with a minute aperture in the centre occurs; and 

 above the septum is occasionally a collection of tiie small 

 ovoid fgecal masses and other debris, so that this region of 

 the tube is rendered opnque " *. The rings on the tubes were 

 very iriegular and only a few were well pronounced. The 

 tube obtained at Station 23 a was fragmentary and resembled 

 the quill-like tube of Hyalincecia tuMcola, but no valves or 

 septum was present. Those dredged at Kinnaird Head and 

 Deep were taken along with several Polynoidse, Serpulidaj, 

 and Terebellidse, and, although quill-like, they were brown 

 in colour and very much coarser than that previously men- 

 tioned. One measured about 8 inches long and was annulated 

 at short but faiily regular intervals, and every tenth or 

 fifteenth ring was stronger and better made than the others. 

 Another had a very marked septum at one end. One of 



* Vide ' Cliallenger ' Report, vol. xii. p. 376, pi. xliv. 10 a. 



