134 '■ ENDEAVOUR " SCIENTIFIC RESULTS. 



Nereis arenaceodentata, Moore. 

 (Plate xlvi., figs. 1-3.) 



Nereis arenaceodentata, Moore, Proc. Acad. Nat. Sci. Phila- 

 delphia, 1903, p. 720. 



A single complete specimen of this small species is present. 

 Its colour is pale pinkish brown in spirit. 



The body is broadest anteriorly, and tapers backwards ; 

 the parapodia are long, increasing in length posteriorly ; their 

 length is as great as the width of the body. 



The worm measures 22 mm. in length by 2.25 mm. across 

 the body, and 3.25 mm. over the parapodia anteriorly ; but 

 posteriorly these latter numbers are 1.25 mm. and 3 mm. 

 respectively. 



Although the present specimen agrees in all essentials with 

 Moore's species, yet, since that has been recorded only from 

 the Atlantic coast, and the occurrence of the same species in 

 two such widely different and dissimilar areas is so rare, if 

 not unknown amongst Annehds, it is desirable that an account 

 of this individual should be put on record and illustrated, so 

 that any doubts about the identity may be set at rest, or at 

 least the material provided for criticism. These notes and 

 figures were, I need scarcely say, made before I became 

 acquainted with Moore's account. 



The prostomiuiii is broader than long, \\ hich may be due in 

 part to the protrusion of the pharynx, stretching the base. 

 The eyes are large, the anterior pair larger than the posterior. 

 The anterior pair as usual rather more widely separated than 

 the posterior, to which they are closely placed. Moore shows 

 them to be of the same size and in contact. 



The tentacles are short,,less than half the length of the pros- 

 tomium. The palps are very large, and broad. 



Of the peristomial cirri the posterodorsal, that is the upper- 

 most, is longest, reaching to the back of the fourth chaeti- 

 gerous segment ; the dorsal anterior, nearly as long, reaching 

 to the anterior margin of this segment ; the two ventral much 

 shorter, scarcely reaching to the end of the second segment. 

 In this respect there is a difference, for what it may be worth, 

 from Moore's account and figure. 



The parapodia are all ahke, relatively long ; the various 

 lobes pointed, distinctly separated and somewhat divergent. 



