192 U.S. NATIONAL MUSEUM BULLETIN 227 



Tentacular segment with ventral tentacular cini subequal to an- 

 tennae, without dorsal tentacular cirri. Parapodia (fig. 486) with 

 acicular lobes sharply conical, with anterior lamellae rudimentary. 

 Notopodial posterior lamellae bilobed, as long as or shorter than the 

 acicular lobes. Neuropodial posterior lamellae simple, oval, shorter 

 than the acicular lobes. Dorsal cirri long, digitiform; ventral cirri 

 conical. Branchiae long, cylindrical, involute, beginning on setigers 

 10-15 and continuing up to last 14-40 segments. Preacicular setae 

 long, barred; postacicular setae very long, den tided. Proboscis 

 with subterminal papillae in 14 longitudinal rows (with some additional 

 papiUae anteriorly, distributed irregularly), 10-20 per row. 



Biology. — Dredged on bottoms of mud, sandy mud with red 

 algae. 



Material examined.— ^Z6a//'oss Station 2231, 38°29' N., 73°09', 

 W,, 965 fathoms, 1883; Gulf of St. Lawrence (south Anticosti Island, 

 120 fathoms). 



Distribution. — Widely distributed in the Arctic. Also Bering 

 Sea, north Japan Sea, Gulf of St. Lawrence, off Labrador, off Chesa- 

 peake Bay, south to Portugal, Mediterranean. In 3 to 4,001 fathoms. 



Aglaophantus circinata (Verrill, 1874) 



Figure 48a 



Nephthys circinata Verrill, in Smith, Harger, and Verrill, 1874, p. 38. 

 Nephtys macroxira Hartman, 1942c, p. 113, fig. 9/i; 1944a, p. 339, pi. 15, fig. 

 11.— Not Schmarda, 1861. 



Description. — ^Length up to 50 mm., width up to 5 mm. Prostom- 

 ium subpentagonal, anterior margin thin, spatulate with translucent 

 areas near bases of frontal antennae, with antennae subequal or 

 ventral pair larger. Tentacular segment enlarged laterally, with 

 ventral tentacular cirri larger than the antennae, without dorsal 

 tentacular cutI. Parapodia (fig. 48a) with conical acicular lobes. 

 Notopodium with rudimentary anterior lameUa, a bilobed posterior 

 lamella consisting of a large foliaceous upper part and small short 

 lower part. Neuropodium with short bilobed anterior lamella con- 

 sisting of a longer upper part and shorter rounded lower part, with 

 a large ligulate posterior lamella directed obliquely upward and 

 outward, being longest in the upper part. Dorsal cirri flat, foliaceous, 

 longer than wide, with pointed tip. Branchiae cirriform, involute, 

 beginning on setiger 2 and continuing to near posterior end. Pre- 

 acicular setae short, barred; postacicular setae long, smooth. 



Proboscis with subterminal papUlae in 14 longitudinal rows (plus 

 some additional papiUae in anterior part, irregularly arranged), 

 each row consisting of 8 or so larger papillae, followed by 2 to 4 or 

 numerous smaller papUlae. 



