136 " ENDEAVOUR " SCIENTIFIC RESULTS. 



Genus Ceratonereis, Kinberg. 



Ceratonereis falcaria, Willey. 



(Plate x\\±, figs. 4-10.) 



Ceratonereis falcaria, Willey, Ceylon Pearl Oyster Fisheries,, 

 pt. iv., Suppl. Rep.,, XXX., — Polychseta, 1905, p. 272. 



A single specimen of a small worm seems to be identical 

 with Willey 's species. 



Its length is 20 mm., its breadth 1.25 mm. Its diameter 

 is nearly uniform for the 60 segments of which it consists. 



The parapodia are short, less than half the diameter of the 

 body ; the dorsal cirrus is very long. 



The prostomium is longer than its basal breadth and the 

 preocular region is narrow and deeply grooved dorsally in the 

 median line, giving the impression of a deep frontal incision, 

 which, however, is scarcely existent in this indi\adual (Fig 4). 

 The tentacles are short, about half the length of the prosto- 

 mium. The palps are relatively large. 



The four eyes are large, nearly equal in size, and the two 

 on each side are placed in nearly a straight fore and aft line, 

 so that the four form a square. 



The tentacular cirri appear to be short and stout, the 

 longest reaches only to the back of the first chsetigerous 

 segment ; the next only touches the hinder margin of the 

 peristomium. They are smooth. 



The parapodia have four lobes nearly equal in length' 

 short and rounded. The no to podium and neuropodium are 

 not very distinctly separated. The notopodial ligule is rather 

 smaller than the middle ligule (or lip of dorsal chsetophore). 

 The neuropodial ligule is stouter than the upper one. The 

 dorsal cirrus is more than twice the length of the uppermost 

 ligule (PI. xlvi., fig. 5). 



The posterior feet differ a httle from the anterior (PI. xlvi.^ 

 fig. 6). The upper hgule is much shorter than the middle,, 

 which is now the longest of the four lobes. 



The chsetge of the notopodium exhibit the remarkable 

 change that Willey describes in his account of the species, 

 that is, the homogomph spinigers of the anterior feet (PI. 

 xlvi., fig. 7) are, in the posterior feet, replaced by a couple 

 of thick brown homogomph falcigers, of AVhich the appendix 



