180 STREBLOSGMA. 



figure of the hook has a very long base and shows only a single tooth above the main fan^ 

 (and resembles that of T. cincinnatiis). 



The tube is composed of secretion to which fragments of shells or entire uni- and 

 bivalves, pieces of heart-urchin, fragments of Oellepora, and numerous other structures 

 are attached, and it much resembles that of Thelepus cincinnatiis, var. andreanse. Lepido- 

 notus squamatus occurred as a commensal in the tube of an example dredged in 81 fathoms 

 by the " Porcupine " off Cape Finisterre ; and Mr. Southern mentions another commensal, 

 viz., Polynoe scolopendrina, in Clew Bay. 



Reproduction. —An example from Lussin in the Adriatic forwarded by Prof. Grube 

 had its ccslom crowded with large ova. It was probably procured in summer. Mature 

 specimens (as T. setosus) are found with pale salmon-coloured eggs in August (Southern). 



Thelepus setosus, De Quatrefages (1865) and other authors, seems to be allied in the 

 closest manner to this species. Descriptions do not enable a definite distinction to be 

 made, and the same result ensues on the examination of specimens kindly forwarded 

 by Mr. Southern from Blacksod Bay. No clear separation could be made. 



Fauvel recently has studied numerous specimens of Thelepus spectabilis, from the 

 Falkland Islands, and found them identical with the Thelepus setosus of De Quatrefages, 

 so common near Cherbourg. He queries if the latter is not T. triserialis, although the 

 hooks are slightly different. The conclusion had already been drawn from descriptions 

 that they could not be separated. This author, further, is of opinion that the Neottis 

 antarcticus, Mcintosh, is the same form, but the marked shortness and depth of the 

 base of the hooks, the different outline below the stud near the tip, as well as the 

 frequent presence of a larger spine on the crown in lateral view in Thelepus setosus 

 are noteworthy, though a margin is necessary for variation. 



This form occurs from Polperro in preparation 62 . 7 . 12 . 45 in the British Museum. 

 It is labelled " Terebella nebulosa." 



Genus CLIIL— Streblosoma, Sars, 1871. 



Cephalic lobe truncate anteriorly, and the dorsal collar is devoid of eye-specks in the 

 preparations. Supra-oral arch flat, and the post-oral lip longer than in Thelepus. Body 

 enlarged anteriorly, but gradually diminishing to a slender tail. Branchiae three pairs 

 of simple filaments on the second, third and fourth segments, but] their position and 

 relationship to the setigerous processes differ from those of Thelepus. ^The bristles 

 commence on the second segment, and differ from those of Thelepus by their great length, 

 and more lustrous condition. Hooks commence on the fifth segment, are smaller than in 

 Thelepus, uniserial, with two prominent teeth above the main fang ; a process for the 

 ligament occurs on the anterior outline and the prow is prolonged downward and forward 

 beyond it. The anterior nephridia (in the fifth segment) are smaller than the posterior, 

 which appear to increase from the diaphragm backward. Tube of muddy sand in fine 

 grains. The genus extends to America (Verrill). 



Verrill 1 (1900) observes that the title Grymxa is preoccupied, and that therefore 

 1 'Trans. o£ the Connect. Acad./ vol. x ; p. 661. 



