126 U.S. NATIONAL JMUSEUM BULLETIN 227 



Distribution. — Norway, English Channel, Baltic, Mediterranean, 

 Adriatic, Black Sea, Maine to Massachusetts, Antarctic, New Zea- 

 land, South Africa, Chile. In low water to 25 fathoms; sexual 

 epitokes in surface waters. 



Syllides setosa Verrill, 1882 



Figure 36a 



Syllides setosa Verrill, 1882, p. 369.— Sumner, Osburn, and Cole, 1913, p. 615.— 



Hartman, 1944a, p. 339, pi. 24, fig. 11. 

 Syllides verrilli Moore, 1907, p. 448, figs. 1, 2. 



Description. — Known only from the sexual epitokes found in 

 surface waters. Length up to 3 mm., width up to 0.3 mm., segments 

 up to 50. Prostomium subqiiadrate, closely united to tentacular 

 segment; palps short, bulbous, directed ventrally, scarcely visible 

 dorsally. Single upper simple seta bifid distally (appears to be 

 a modified compound seta that has lost its blade and the distal bifid 

 tip of the shaft has been worn down). Colorless or dull orange yellow. 



Biology. — Sexual epitokes found in surface waters during summer 

 months, in evening (June, July, August, September, Vineyard Sound, 

 Massachusetts). Found on mussel beds (Moore). 



Material examined. — Massachusetts (Fisheries Dock, Woods 

 Hole, evening, at light, June 8, 1954). 



Distribution. — Massachusetts (Vineyard Sound). Low water; 

 sexual epitokes in surface waters. 



Genus Streptosyllis Webster and Benedict, 1884; emend. Southern, 



1914 



Type (monotypy): Streptosyllis arenae Webster and Benedict, 1884. 



Both species have the body elongate, widest in middle third, 

 tapering anteriorly and posteriorly, convex dorsally, flattened ven- 

 trally. Prostomium subquadrangular, with 3 pairs of eyes, anterior 

 pair small, near lateral antennae, 2 more posterior pairs larger, closely 

 approximated and may be merged, with 3 clavate or c^dindrical an- 

 tennae, with palps sAvollen basally and fused on inner part, distal half 

 being conical, pointed. Tentacular cirri 2 pairs, similar to the an- 

 tennae. Parapodia mth an enlarged, knobbed aciculum in a certain 

 number of anterior segments (fig. Slk) ; rest of segments with knobbed 

 acicula but not especially enlarged. Setae of 2 kinds, a single (rarely 

 2) upper simple seta and numerous compound ones. Dorsal cirri 

 variable, may be clavate or cylindrical, wrinlded irregularly or articu- 

 late. Ventral cirri nearly as long as or longer than the dorsal cirri. 

 Anal cirri 3, a pair of long lateral ones and a short median one. Pro- 

 boscis unarmed, with a circle of papillae. 



