POLYCHAETE WORMS, PART 1 69 



Tentacular cirri 4 pairs, on first 3 segments (first segment may be rudimentary 

 or fused with second, not visible dorsally, figs. 17, a,b: 18a) 2 



2. Prostomium with four frontal antennae, without median antenna 3 



Prostomium with a median antenna in addition to four frontal antennae 



(figs. 176, 19a). Prostomium suboval or subcorneal, without nuchal 

 tubercle 4 



3. First 2 segments fused, well developed, from which the first 3 pairs of 



tentacular cirri emerge (fig. 17a). Prostomium suboval, with or without 



nuchal tubercle Paranaitis (p. 75) 



First segment rudimentary, not visible dorsally, with first pair tentacular 

 cirri lateral to prostomium. Prostomium cordiform, with nuchal tubercle 

 in posterior notch (may be withdrawn, fig. 18a). . . . Phyllodoce (p. 77) 



4. With nuchal epaulettes (fig. 176) Notophyllum (p. 83) 



Without nuchal epaulettes 5 



5. All 3 tentacular segments distinct dorsally (fig. 19a). Proboscis thickly 



papillated Eulalia (p. 84) 



First tentacular segment rudimentary, not distinct dorsally, with first pair 

 tentacular cirri lateral to prostomium (fig. 21a). Proboscis smooth, 

 wrinkled or sparsely papillated Eumida (p. 88) 



Genus Eteone Savigny, 1820 



Type (monotypy): Eteone fiava (Fabricius, 1780). 



The species represented have the body linear elongate, slender, 

 somewhat flattened dorsoventrally, with ninnerous segments (up to 

 100-400 or so), tapering gradually anteriorly and posteriorly. Pro- 

 stomium (fig. 16a) trapezoidal to sub triangular, widest basally, taper- 

 ing gradually anteriorly to a rounded area, with 4 subequal small 

 frontal antennae, without a median antenna; with a small median 

 nuchal tubercle (may be withdrawn and difficult to detect); with a 

 pair of lateral nuchal slits (difficult to detect); and with a pair of 

 deep set eyes on posterior part of prostomimii (may not be visible 

 when preserved and opaque). 



First or tentacular segment achaetous, with 2 pairs of filiform 

 tentacular cirri. Second segment without dorsal cirri, with or with- 

 out setigerous lobes, with foliaceous ventral cirri. Ventral cirri elon- 

 gate oval, about as long as setal lobe. Parapodia uniramous, slightly 

 bifid distally; setae compound, with blades tapering to capillary tips. 

 Proboscis with a circlet of soft papillae around opening, with surface 

 smooth, rugose or irregularly papillate, with a pair of jaws inside 

 proboscis (not visible unless dissected). 



Characteristically burrowing forms. 



Key to the New England Species of Eteone 



1. Segment 2 with ventral cirri only, without setigerous lobe. Tentacular cirri 

 unequal, ventral pair 2 to 3 times longer than dorsal pair (fig. 16a). Anal 



cirri subulate, tapering (fig. 166) E. lactea 



Segment 2 with setigerous lobe and setae well developed 2 



