Polydora Mud Worm

Polydora ligni Webster

Polydora ciliatum Agassiz, 1867, pp. 323–330, pls. 9–10.—Verrill, 1873, pp. 51, 309, 345, 364, 453, 603, pl. 14, fig. 78. Not Johnston, 1838.

Polydora littorea Verrill, 1881, p. 301 (nomen nudum).—Hartman, 1944, pp. 336, 340, pl. 18: fig. 10, not pl. 18: fig. 9.

Polydora ligni Webster, 1879b, p. 119, pl. 5: figs. 45–47.—Webster and Benedict, 1884, p. 729.—Söderström, 1920, pp. 265–267, figs. 170–174.—Cowles, 1930, p. 341.—Berkeley and Berkeley, 1936, pp. 471–472; 1952, p. 19, figs. 31–33; 1954, p. 464.—Friedrich, 1937, pp. 345–347, figs. 5–6; 1938, p. 133.—Rioja, 1943, pp. 232–244; 1947, p. 207.—Mortenson and Galtsoff, 1944, pp. 164–165.—Graham and Gay, 1945, p. 379.—Hartman, 1941, pp. 309–310, figs. 47–49; 1945, p. 32; 1951, p. 82; 1954, p. 10; 1961, p. 29; 1969, pp. 137–138, figs. 1–6.—Hartman and Reish, 1950, p. 28.—Smidt, 1951, pp. 63–65.—Hannerz, 1956, pp. 106–111, figs. 37–38.—Jones, 1961, p. 266.—Eliason, 1962, p. 52.—Reish, 1963a, pp. 25, 30; 1963b, pp. 265–270; 1964a, pp. 202–207; 1964b, pp. 86–92.—Wells and Gray, 1964, p. 73.—Galtsoff, 1964, p. 421–425.—Cory, 1967, pp. 71–89.—Berkeley, 1968, p. 560.—Blake, 1969b, pp. 4–10, figs. 1–4.

Polydora amarincola Hartman, 1936, p. 49, figs. 6–10.

MATERIAL EXAMINED.—Maine (Cobscook Bay; Lamoine Beach; Penobscot River; Damariscotta River; Sheepscot River), Massachusetts (Woods Hole; West Falmouth; Hadley Harbor), Connecticut (Noank), New Jersey (Raritan Bay, coll. D. Dean), North Carolina (Beaufort).

DESCRIPTION.—Largest specimens measure 32 mm in length and have up to 80 segments. The prostomium is bifurcated and flares laterally. There are four eyes, arranged as a trapezoid. A nuchal tentacle is present on the caruncle at about the level of setiger 1. The caruncle continues posteriorly as a narrow ridge through setiger 3. A ciliated groove lies on either side of the caruncle (Figure la).

Setiger 1 has well-formed parapodial lobes but contains only capillary neurosetae (Figure 1b). Setigers 2–4 and 6 contain fascicles of finely winged capillary setae. After setiger 6 the number of notosetae gradually diminishes, until in posterior segments only a tuft of long capillary setae remains. Bidentate hooded hooks begin on setiger 7 (Figure 2d, e). There are up to 15 hooks per neuropodium and no accompanying capillary setae. Hooks of the same neuropodium may have the main fang either at a right angle to the shaft or bent to about 70°. A constriction and curve are prominent on the shaft. A striated hood covers the teeth.

Setiger 5 is modified to include a row of heavy spines with closely adhering companion setae (Figure 2a–c). The former have a small accessory tooth which may be considerably worn. The latter have a delicate feathery end; when depressed, the tip is seen to be forked.

Branchiae are long and thin, beginning on setiger 7 and continuing to near the end of the body.

The pygidium is a large, flaring cup with a dorsal gap (Figure 1c).

Color in life is light tan with red blood vessels. Except for lateral black pigment spots often present in juveniles, the body is unpigmented.

DISTRIBUTION.—East and west coasts of North America, Gulf of Mexico and northern Europe.