428 p. W. GAMBLE AND J. H. ASHWORTH. 



A. marina (= A. piscatorum, Lamarck) includes A. 

 tinctoria, Leacli, and A. carbonaria, Leach/ which dif- 

 fered somewhat in colour from more typical specimens. 

 A. n a talis, Girard (1856, p. 88), is nothing more than an 

 ordinary A. marina, in which Girard has mistaken the 

 ventral for the dorsal surface. The smooth dorsal line which 

 he describes as one of the peculiar characters of this worm 

 is the line found on practically all specimens of Arenicola 

 indicating the position of the ventral nerve-cord, its anterior 

 division into two being the usual division into the two 

 metastomial tracts or grooves which mark the position and 

 course of the oesophageal connectives. A. natal is has 

 thirteen pairs of gills, and six pairs of parapodia in front of 

 the first gill, thus exactly agreeing in these respects with A. 

 marina. It was found on Chelsea Beach (Mass., U.S.A.), 

 i. e. well to the northward of lat. 40° N., which, as we have 

 shown, marks the southern limit of A. marina. 



As stated below, Clynienides sulfureus, Mesnil (1897), 

 is now proved to be the post-larval stage of A. marina. 



A. cristata (== A. antillensis, Liitken, 1884) probably 

 also includes A. glacialis, Murdoch,^ from Alaska. The 

 description of this latter species is very brief and insufii- 

 cient, the only characters of real importance mentioned being 

 the presence of eleven branchiferous segments, preceded by 

 six abranchiate segments, thus exactly agreeing with A. 

 cristata. 



Czerniavsky^ describes three new species of Arenicola 

 from the neighbourhood of Sevastopol (Black Sea), viz. A. 

 cyanea, A. dioscurica, and A. Bobretzkii; but these are 

 undoubtedly specimens of A. Grubii, differing from each 

 other only in colour, age, and size. All of them have eleven 

 anterior abranchiate segments, as in A. Grubii, and at 



' 'Eiicyclopsedia Britanuica,' Sujjplenient, vol. i, p. 452. 



2 'Proceedings United States National Museum,' VVasiiington, vol. vii, 

 1884, p. 522. 



* 'Bulletin de la Societe Imperiale des Naturalistes de Moscou,' vol. Ivi, 

 1881, pp. 353—356. 



