Protis pacifica Moore 1923

Protis pacifica Moore, 1923

Protis pacifica Moore, 1923, pp. 253–254.—Hartman, 1955, pp. 51, 52, pl. 4; 1959. p. 588; 1960, pp. 163, 164; 1963. p. 79.—Hartman and Barnard, 1958, pp. 2, 10, 11, 27, etc., 65.

MATERIAL EXAMINED.—Off Brockway Point, Santa Rosa Island, California: holotype and 4 para-types, “Albatross” sta. 4433, 1904 (USNM 17434, 17435).

DESCRIPTION.—Tube white, straight or more or less tortuous and bent, approximately cylindrical, of circular cross section as its distal and free end but slightly flattened where attached to the substratum. No keels, surface somewhat rugose due to the presence of irregularly spaced annulated growth rings. Longest tube described 65 mm, thickest one 4.2 mm at the mouth. The length of the animal may attain 40 mm. Sometimes more than 60 abdominal segments. Collar divided into 3 lobes, the laterodorsal ones continued in long thoracic membranes which are united at the ventral face of the last thoracic segment. Gill tuft without an operculum. Gill lobes short, with the filaments arranged in a semicircle. Up to 20 filaments on each side.

First thoracic segment with capillary setae and stouter special setae, with a well separated distal limbate zone and a proximal wing of about 6 teeth. Segments 2 to 7 with capillary setae and simple limbate ones. Segments 3 to 7 also with sickle-shaped setae and with a short proximal limbate zone preceeding the distal edge with a blunt denticulation. Posterior abdominal segments with long capillary setae. Setae of the anterior segments almost capillary but with a very small narrow limbate edge just below the tip. Thoracic uncini saw-shaped, with 6 to 8 teeth, the anterior one simple, not bifurcate. Abdominal uncini of similar form but rasp-shaped in all segments. Uncini of the posterior segments with more teeth than those of the more anterior segments.

DISTRIBUTION.—In the Pacific the genus Protis is known by one species from off the California coast. The original specimens of Protis pacifica Moore were dredged off Santa Rosa Island (depth about 485 m). Many new records were given by Hartman (1955, 1960, 1963) and by Hartman and Barnard (1958) from deep basins and submarine canyons off California (depths from several hundred meters down to 787 m). It seems to be an exclusively bathyal species.