POLYCHAETE WORMS, PART 1 285 



Orbinia (Orhinia) ornata (Verrill, 1873a) 



Figure 75,a,b 



Aricia ornata Verrill and Smith, 1874, pp. 50, 71, 302. — Webster and Benedict, 

 1884, p. 724.— Andrews, 1891a, p. 292.— Sumner, Osburn, and Cole, 1913, 

 p. 623. 



Orbinia ornata Hartman, 1942b, p. 61; 1944a, p. 340, pi. 18, fig. 7, pi. 19, fig. 16 

 (as Scoloplos armiger); 1945, p. 28. 



Phylo ornatus Hartman, 1951, p. 79; 1957, p. 265, pi. 24, figs. 1-10. 



Description. — Length up to 250 mm., width up to 7 mm., segments 

 up to 300. With middorsal reddish glandular areas beginning be- 

 tween setigers 7-8. Thoracic setigers (fig. 75, a, 6) about 24 (19-32). 

 Thoracic neuropodial postsetal lobes with 4-18 papillae, with several 

 rows of crotchets (2-7 rows). Crotchets golden yellow or brown, 

 faintly crenulate, curved, with blunt tips. A single posterior row of 

 curved crenulate setae present, tapering to fine tips. In the more 

 posterior thoracic neuropodia, some the the crotchets in the anterior 

 row or the upper part of the lobe may be darker (perhaps worn ; they 

 do not appear to be specialized as in Phylo). 



Abdominal region with paired straplike branchiae and paired digiti- 

 form notopodial postsetal lobes subequal, the branchiae as well as the 

 inner sides of the notopodial lobes ciliated, thus forming three lon- 

 gitudinal ciliated grooves. Neuropodia shorter, with, tips bilobed, 

 with two short curved acicula and long slender capillary setae. With- 

 out interramal cirri. Subpodal part joining the rest of the body 

 entire, smooth or undulate, without subpodal papillae or ventral cirri 

 except on few (2-6) transitional abdominal segments, where there 

 may be 1-2 subpodal papillae. Subpodal ventral or stomach papillae 

 on 10-24 segments, beginning on about setiger 14 (12-15), few at 

 first, becoming more numerous and forming a nearly complete semi- 

 circular row, then becoming fewer and disappearing on about setiger 

 36 (20-38). Anal ring with a pair of long, very slender anal cirri on 

 the dorsolateral edge. Extended proboscis soft, saclike, forming a 

 lobulated, rosettelike sac around the mouth. Color: yellow orange, 

 yellowish red, deep red, reddish brown with bright red dorsal branchiae 

 and parapodial lobes. 



Biology. — They are found at low water on sandy or muddy shoals, 

 muddy sand, gravelly sand. Dredged in shallow water on bottoms of 

 silty sand. May form delicate mucous sandy tubes. Autotomize 

 readily when removed from the sand. Sexually matiue in the Woods 

 Hole region, Massachusetts and Beaufort, North Carolina, in June and 

 early July (Moore, ms. and Hartman, 1945). Eggs pale or yellowish. 



Material examined. — Numerous specimens from Massachusetts 

 (Cape Cod, Provincetown, Wellfleet, Truro, Barnstable; Woods Hole 

 region. North and South Falmouth, Hadley Harbor, Nonamesset 



