POLYCHAETE WORMS, PART 1 203 



Wentworth), Massachusetts (Georges Bank, 37-136 fathoms; Massa- 

 chusetts Bay off Plymouth, 17 fathoms). 



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

 Faroes to France, Hudson Bay, Labrador to Massachusetts, Alaska to 

 southern California, north Japan Sea to Japan, China. Low water to 

 500 fathoms. 



Nephtys discors Ehlers, 1868 



Figure 51, e,/ 



Nephthys discors Verrill, 187.3b, p. 103.— Webster and Benedict, 1887, p. 709. 

 Nephtys discors Pettibone, 1954, p. 270. 



Description. — Length up to 300 mm., width up to 12 mm., seg- 

 ments up to 120. Tentacular segment with dorsal pair tentacular 

 cirri subequal to or about half as long as ventral pair. Parapodia 

 with notopodial acicular lobes l>ilobed in anterior and middle regions, 

 rounded in posterior region. Neuropodial acicular lobes slightly bi- 

 lobecl to rounded. Anterior lamellae rudimentaiy; posterior lamellae 

 in anterior and middle regions (fig. 51e) large, foliaceous, extending 

 well beyond the acicular lobes. In the posterior region (fig. 51/) 

 posterior lamellae short, inconspicuous. Tips of acicula covered 

 with yellow chitinous plates. Preacicular setae short, barred; post- 

 acicular setae longer, finely spinous. Ventral cirri short, conical; 

 dorsal cirri flattened, triangular, pointed. Branchiae begin on seti- 

 ger 6, small at fii"st, become larger, inflated basally, hooked distally, 

 rudimentar}^ on posterior half of body. 



Biology. — Found at low water on bottoms of muddy sand, gravelly 

 sand, among mussels. Dredged on bottoms of mud, gravelly mud, 

 stones, rocks, worm tubes. 



Material examined. — Gulf of St. LawTcnce (Bay of Chaleurs, 6 

 fathoms). New Brunswick (St. Andrews), Maine (Starboard Creek, 

 Machias Bay; Rock ledge opposite C-1 Buoy, Sheepscot River, Booth- 

 bay Harbor region), Japan (ofl' Kamchatka, 54° N., 155°E., 53 fathoms, 

 M. Imajima, collector). 



Distribution. — Alaskan Arctic to southern California, Japan, 

 Gulf of St. LaA\Tence to ]Maine. Low water to 268 fathoms. 



Nephtys caeca (Fabricius, 1780) 



Figure 516 



Nephthys caeca Verrill, 1881, pp. 294, 295, 296, 307, 314.— Webster and Benedict, 

 1887, p. 709.— Whiteavcs, 1901, p. 82.— Not Moore, 1909a, p. 137( = A^. 

 ci7zato).— Kindle, 1917, p. 150.— Fauvel, 1923, p. 365, fig. 142,c-Z; 1933, 

 p. 39.— Prdfontaine, 1932, p. 207.— Procter, 1933, p. 136.— Annenkova, 1937, 

 p. 164; 1938, p. 163.— Berkeley and Berkeley, 1948, p. 54, figs. 80-81.— 

 Uschakov, 1955, p. 217, fig. 68.— Clark, 1960, p. 20. 



569-457—63 14 



