124 U.S. NATIONAL MUSEUM BULLETIN 227 



August, and September. They are luminescent, with a bright green 

 Hght. 



Material examined. — Numerous specimens from Vineyard Sound, 

 Massachusetts, low water to 15 fathoms; numerous sexual epitokes at 

 surface. 



Distribution. — Massachusetts to Virginia, English Channel, 

 Mediterranean. In low water to 15 fathoms; sexual epitokes at 

 surface. 



Genus Syllides Oersted, 1845a 



Type (monotypy) : Syllides longocirrata Oersted, 1845a. 



Both species have the body slightly flattened, wider in the middle 

 region, tapering gradually anteriorly and posteriorly. Prostomium 

 with 2 pairs of large red eyes and usually a pair of small ocular spots 

 near the lateral antennae. Antennae, tentacular cirri, and first few 

 dorsal cirri club shaped, inflated distally, smooth or feebly wrinlded. 

 Rest of dorsal cirri more slender, tapering, distinctly articulated, 

 tending to be alternately longer and shorter. Ventral cirri elongate, 

 slender, extending beyond the parapodial lobes and, in the more 

 posterior segments, may extend about as far as the tips of the setae. 

 Parapodia uniramous, with a single (rarely 2) upper simple seta and 

 numerous compound setae with blades short to long, tapering to 

 fine bidentate tips. Anal cirri 3, a long articulate lateral pair and a 

 short median one. Proboscis short, unarmed, with a circlet of papillae. 

 When mature, they form sexual epitokes, eyes may be considerably 

 enlarged, long capillary setae are formed above the neuropodia, and 

 the sex products become massed in the more posterior segments. 



Key to the New England Species of Syllides 



1. Prostomial palps extend anteriorly, of about the same length as the prostomium 

 (fig. 366). Longest dorsal cirri with 14-25 articles. Sexual epitokes with 



swimming setae beginning on setigers 11-12 S. longocirrata 



Prostomial palps short, bulbous, extending ventrally, scarcely visible dorsally 

 (fig. 36a). Longest dorsal cirri with 7-8 articles. Sexual epitokes with 

 swimming setae beginning on setigers 8-9 S. setosa 



Syllides longocirrata Oersted, 1845a 



Figure 366 



Sxjllides convoluta Webster and Benedict, 1884, p. 709, pi. 2, figs. 12-16; 1887, p. 



717. 

 Syllides longocirrata Webster and Benedict, 1887, p. 717. — Fauvel, 1923, p. 284, 



fig. 108,a-g.—Fyfe, 1952, p. 12.— Banse, 1959, p. 430.— Day, 1960, p. 310.— 



Wesenberg-Lund, 1962, p. 59.— Eliason, 1962, p. 241. 

 Syllides longocirratus Ehlers, 1897, p. 45. 

 Syllides longicirrata Marinov, 1959, p. 84, fig. 1. 



Description. — Length up to 7 mm., width up to 1 mm., segments 

 up to 50. Prostomium suboval, wider than long; palps usually extend 



