92 



its larger bulbous end. As transparent objects the filaments 

 (radioles) present an interrupted dark line in the centre, pro- 

 bably from a blood vessel, and the pinna? are richly ciliated. 



The question as to whether the complex spirals in this large 

 form (double the size of that procured by the "Challenger") 

 are the product of age is interesting, and the fact that each side 

 differs from the other in the character of the spirals shows that 

 considerable variation is possible. 



The collar commences by a wide fan-like flap at each side 

 dorsal Iv, and extends round the ventral border to the other 

 side The first or lateral flap is partially separated by a fissure 

 from the rest of the collar, which otherwise is continuous. The 

 lateral flap of the collar is continuous again dorsally with the 

 loosely folded membrane which flanks the anterior or thoracic 

 region, and which passes between each of the bristle-bundles 

 to be attached as a folded or frilled band to the ventral surface, 

 embracing on each side the soft pad for the rows of hooks. 

 Dorsally, the whole forms a continuous membrane, for it is 

 attached on the dorsal aspect of each bristle-bundle, and it is 

 highly vascular, every part of it being permeated by the finely 

 branched vessels with their dark blood. Posteriorly the ventral 

 edges of the membrane are joined by a thicker fold (already 

 alluded to), and which probably contains glandular elements 

 like the area in front. 



The anterior regions has seven pairs of golden bristle-bundles, 

 each consisting of a dense group of fine bristles with delicately 

 tapered tips and narrow wings. The great number of these 

 slender bristles in a tuft is a feature of moment. No spine is 

 present. The bristle-bundles are nearly of the same size from 

 the first to the last. They appear to correspond in minute 

 structure with those of Protitla aipciisis. 



In the same way the anterior hooks appear to dift'er onlv in 

 size, for the curves are the same. These rem;irks also applv to 

 the posterior hooks. 



The species occupies a large white, calcareous tube (which 

 was absent in the "Challenger" collections), sinuous in 

 outline, and having an average diameter of 13-14 mm. It is 

 smooth internallv, but roughened externally bv various growths 

 such as tubes of Filigraiin, patches of Cellcpora (Lepnilia ), 

 Bala III, coarse sand and Mclobesla. 



The many close structural resemblances between this and the 

 European species {Proliila hibulaiia, Montagu) raises some 

 doubt as to the specific distinction on grounds so slender as 

 the slight modification of hooks and other parts. Its much 

 larger size m South African waters will account for some of 

 these variations. On the whole it mav be considered as a 

 variety of the European species. 



[PUBl.lSHKD 25TH Jl NK, ig04.] 



