POLYCHAETE WORMS, PART 1 281 



less wide and flattened, tapering rather abruptly anteriorly, abdominal 

 region much longer, semicircular in cross section, tapered gradually 

 posteriorly, often fragmenting. Prostomium conical, without append- 

 ages, without eyes. Single achaetous tentacular or buccal segment, 

 without tentacular cirri. The buccal segment and first 2 setigerous 

 segments involved in the mouth. Thoracic region consisting of 

 14-37 setigers. Notopodia with a simple digitiform postsetal lobe 

 (may sometimes be bifurcated in 0. norvegica), with a radiating bundle 

 of crenulate capillary setae. Neuropodia thick, cushionlike, with a 

 postsetal fringe of papillae, with transverse rows of crotchets (blunt 

 tips) or pseudocrotchets (tips enclosed in pointed sheaths) and 

 crenulate capillary setae. 



Abdominal region with parapodia directed dorsally. Notopodia 

 similar to those of thoracic region except they are more elongate, 

 sometimes with few forked setae among the capillary crenulate 

 setae (broken crenulate capillaries?). Neuropodia short, cylindrical, 

 bilobed at tip, with few short acicula and bundle of crenulate capillary 

 setae. Branchiae begin on about setiger 5 (4-6), paired, simple, 

 straplike, cihated up to near distal tip, becoming long, ligulate in 

 abdominal region. 



Key to the New England Subgenera and Species of Orbinia 



1. With heav}' spear-shaped or spikehke spines on some posterior thoracic 



neuropodia (fig. 75c) . . (subgenus Phylo) 2 



Without heavy spines . . (subgenus Orbinia, sensu stricto) 4 



2. With subpodal ventral or stomach papillae on some anterior segments (fig. 



756) 3 



Without subpodal ventral papillae O. (Phylo) norvegica 



3. With interramal cirri on some anterior abdominal segments (fig. 75/). 



O. (Phylo) niichaelseni 

 Without interramal cirri (fig. 75g) O. (Phylo) kupfferi 



4. With ventral cirri in abdominal parapodia (fig. 75d) , . O. (Orbinia) swani 

 Without ventral cirri O. (Orbinia) ornata 



Orbinia (Phylo) norvegica (Sars, 1872) 



Figure 75c 



Aricia norvegica Sars, 1873, p. 236, pi. IC, figs. 1-8. — Fauvel, 1927, p. 17, fig. 

 5,m-p.— Annenkova, 1937, p. 168; 1938, p. 170.— Wesenberg-Lund, 1950b, 

 p. 75.— Uschakov, 1955, p. 257, fig. 85.— EHason, 1962, p. 260. 



Aricia nuda Moore, 1911, p. 311, pi. 21, figs. 172-176.— Fauvel, 1932a, p. 162, 

 fig. 25. 



Phylo norvegica St^p-Bowitz, 1948a, p. 66. 



Phylo nudus Hartman, 1957, p. 268; 1960b, p. 108. 



Phylo norvegicus Hartman, 1959a, p. 367.— Kirkegaard, 1959, p. 13. 



Description.^ — Length? (more than 20 mm.), width up to 6 mm., 

 segments numerous (more than 40). Thoracic setigers 16-17. 



