POLYCHAETE WORMS, PART 1 119 



Palps broad, flattened, united on basal third, changeable in form, 

 often turned under ventrally (fig- 34a). Parapodia with setae com- 

 pound, similar throughout; ventral cirri short, conical. Anterior 

 border of proboscis with a circlet of papillae; anterior border of 

 chitinous lining -wdth a single large median tooth and finely denticled 

 rim (fig. olp). Mature forms becoming epitokous, with swimming 

 setae forming on more posterior segments (figs. 33, 34(i). 



Key to the New England Species of Eusyllis 



1. Tentacular segment with a distinct, wide, crescent-shaped nuchal fold covering 

 the posterior part of the prostomium (fig. 31?i). Distal blades of compound 

 setae short, bidentate (fig. 31o). Dorsal cirri short, those of median and 

 posterior regions shorter than body width. Ventral cirri of first setiger not 



enlarged E. blomstrandi 



Tentacular segment with a slightly marked ridge but not a distinct nuchal fold 

 (fig. 33). Distal blades of compound setae longer, bidentate (fig. 34&). 

 Dorsal cirri long — 4 to 8 times as long as the body width. Ventral cirri of 

 first setiger much larger than the following, flattened, foliaceous (fig. 34a). 



E. lamelligera 

 Eusyllis blomstrandi Malnigren, 1867 



Figure 31,?i-p 



Eusyllis phosphorea Verrill, in Smith, Harger, and Verrill, 1874, pp. 20, 39, pi. 7. 



fig. 2.— Hartman, 1944a, p. 338, pi. 25, fig. 4. 

 Eusyllis blomstrandi Fauvel, 1923, p. 293, fig. 112,/i-m.— Pettibone, 1954, p. 260, 



fig. 2S,g-i] 195Ca, p. 555. 



Description. — Length up to 32 mm., width without setae up to 

 1.2 mm., segments up to 124. Prostomium (fig. 31n) with median 

 antenna up to 3 times the body width, lateral antennae half as long. 

 Antennae, tentacular cirri, anterior dorsal cirri irregularly annulated, 

 especially distally, more or less smooth basally; the more posterior 

 dorsal cirri indistinctly annulated or smooth. Sexual epitokous forms 

 with swimming setae beginning on setiger 17 (13-17), continuing to 

 near posterior end. Body orange or yellomsh. 



Biology. — Dredged on bottoms of mud, sand, gravel, rocks, with 

 hydroids, bryozoans, shells, worm tubes. A few were obtained in the 

 oceanographic fouling studies in the New England region. They may 

 form definite hardened mucous tubes. They are luminescent, giving 

 oft" a bright green light. wSexual epitokous individuals have been found 

 in Alaskan Arctic in August (Pcttibone, 1954), in Labrador in June 

 (Pettibone, 1956a). 



Material examined. — Gulf of St. La\vrence (Bay of Chaleurs, 

 south of Anticosti Island), Maine (Eastport, Mount Desert region), 

 Massachusetts (Georges Bank, Nantucket), 20 to 120 fathoms. 



Distribution. — -Widely distributed in the Arctic. Also Iceland, 

 Ireland to Mediterranean, Labrador to Massachusetts, Bering Sea to 



