Figures 10–11
Clistaxis ? polystrigma Dall 1908: 246.
Type material. Holotype (USNM 110649): San Diego, 92 m (Fig. 10 E).
Other material examined. WASHINGTON: West of Point Chehalis, Washington, 128–137 m depth, 10 Aug 1992, 2 shells, 2.9–5 mm long (LACM 178891).
OREGON: Tillamook Bay, Oregon (45º30.75’N, 124º45.00’W), 640 m depth, 12 Oct 1992,> 20 shells, 2.1–5 mm long (LACM 178892). About 345.6 miles from Cape Foulweather, Oregon (45º00.2’N, 132º12.1’W), 3585 m depth, R/ V Yaquina (BmT-298), 5 Oct 1972,> 20 specimens, 9–16 mm preserved length (LACM 72-261.8). About 345.3 miles from Cape Foulweather, Oregon (44º54.3’N, 132º11.5’W), 3580 m depth, R/ V Yaquina (BmT-299), 6 Oct 1972,> 20 specimens, 9–16 mm preserved length (LACM 72-262.6).
CALIFORNIA: About 226 km west of Point Arguello, Santa Barbara, California (34º42’N, 123º02’W), 4100 m depth, R/ V New Horizon (NH-2704M), 14 Nov 1995, 2 specimens, 9 mm preserved length (LACM 95-130.26).
Description. Live animals unknown. Preserved specimens to 16 mm length. Body very elongate, about four times as long as wide (Fig. 10 A). Cephalic shield elongate, tapering posteriorly. Parapodia inconspicuous, running from near anterior end of body to beginning of posterior shield. Shell internal, occupying the entire posterior shield. Shell to 5 mm, small, globose, oval to elongate, wider anteriorly (Fig. 10 C–D). Apex with an involute spire. Lip not rising above apex. Sculpture composed of faint, densely packed, punctuate striae (Fig. 10 B).
Digestive system with a small, oval buccal bulb, surrounded by central nervous system posteriorly (Fig. 11 C). Two small salivary glands connect on esophagus. Esophagus short and straight. Gizzard large, muscularized. Gizzard plates (3) oval, elongate, smooth (Fig. 10 F–G). Radular formula 12 x 1.0.1. Lateral teeth hook-shaped, with narrow bases and elongate cusps (Fig. 10 I). Fine denticles present on inner middle portion of cusp. Reproductive system with a long and convoluted prostate (Fig. 11 A). Penis complex, with a blunt apex (Figs. 10 H, 11B).
Range. Point Chehalis, Washington to San Diego, California (Fig. 3 B). Depth range 128–4,100 m. Remarks. Dall (1908) stated that the animal is contained within the shell, but the dried holotype shows mantle tissue enveloping the lip, thus the shell is internal as indicated by Gosliner (1996). Description of reproductive system and radula by Gosliner (1996).