POLYCHAETE WORMS, PART 1 293 



ciliated organs near the bases of the notopodia, with unequally bilobed 

 neuropodia. The transitional region with 1-2 extra papillae on the 

 last few thoracic (1-5, fig. 76A) and fu'st few abdominal segments 

 (1-7), then with elongate, thickened, entire subpodal flanges uniting 

 the neuropodia with the sides of the body. Proboscis forming a soft, 

 more or less lobed sac around the mouth. Color: red or reddish 

 orange. 



Biology. — Found at low water on bottoms of sand, fine mud, grav- 

 elh' sand, roots of eelgrass (Zostera). Dredged on bottoms of mud, 

 sand, and various combinations of mud, sand, gravel, stones, rocks. 

 In European waters (Scotland, Holland, Danish waters), they spawn 

 from the end of February to June (Thorson, 1946 ; Smidt, 1951 ; Newell, 

 1954; Anderson, 1959). Fertilized eggs are laid in gelatinous pear- 

 shaped cocoons attached to the sand by a tough string. The larvae 

 hatch from the cocoon after about three weeks when they are in the 

 crawling stage. Pelagic stages are lacking. Larvae of 11 setigers 

 have 2 pairs of large branchiae beginning on setiger 9. Details of its 

 embryology and early development have been worked out by 

 Anderson (1959). 



Material examined. — Off Newfoundland (Albatross Station 2438, 

 46°48' N., 52°34' W., 89 fathoms). Nova Scotia (Clark's Harbor 

 and Partridge Island), New Brunswick (Grand Manan; St. .i\jidrews), 

 Maine (Rock ledge opposite C-1 Buoy, Sheepscot River), Massachu- 

 setts (Albatross III, 40°37' N., 67°28' W., 47 fathoms, R. Wigley), 

 Washington (Crescent Beach near Dutchers Cove, Case Inlet, Puget 

 Sound). 



Distribution. — Circumpolar, widely distributed in the Arctic. 

 Also Iceland, Faroes, Shetlands to France, Mediterranean, Labrador to 

 Massachusetts, Bering Sea to California, Central America (El Sal- 

 vador), north Japan Sea to Japan, South Pacific (Chile), Antarctic, 

 off West and South Africa. Low water to 1,100 fathoms. 



Scoloplos (Scoloplos) acutus (Verrill, 1873a) 



Figure 74g 



Anthosloma acutum Verrill and Smith, 1874, pp. 122, 128, 134, 207, 214, 305. — 



Verrill, 1874b, pp. 351, 355, 367, 384. 

 Scoloplos acutus Verrill, 1881, pp. 301, 305, 309.— Procter, 1933, p. 141. 



Description. — Length up to 40 mm., width up to 1 mm., (2.5 mm.?, 

 Verrill), segments numerous. Prostomium sharply conical, longer 

 than wide. Branchiae begin on about setiger 12 (10-14). Thoracic 

 setigers about 14 (13-15). Thoracic neuropodia with fan-shaped 

 bundles of neurosetae all ending in fine tips, without crotchets. 



