PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON lll(3):535-550. 1998. Pentamera rigida and P. pediparva, two new species of sea cucumber from the west coast of North America (Echinodermata: Holothuroidea) Philip Lambert Natural History Section, Royal British Columbia Museum, P.O. Box 9815 Stn Prov Govt, Victoria, B.C., Canada V8W 9W2 Abstract. — Two new species of the genus Pentamera from the west coast of North America are described, and all known species from the west coast of North and South America are reviewed. Pentamera rigida is a slender, stiff, U-shaped species with five rows of podia. It occurs in sand-gravel substrata from 18 to 421 m between British Columbia and California. The table ossicles of the skin have an angular disc with a broad, low, convoluted spire. Pentamera pediparva has a soft, curved body with five rows of fine podia. It is known from central British Columbia to northern California from 8 to 120 m in mud-gravel or sand-gravel. The table ossicles are small and oval with small, two pillared spires. The taxonomic characters of fourteen species of Pentamera are summarized. Twelve species of Pentamera have been described from the west coast of North and South America (Stimpson 1851, 1864; Lud-wig 1886a, 1886b; Clark 1924; Deichmann 1938a, 1938b). Panning (1949) placed the genus Pentamera in Thyoninae, a new sub-family of Cucumariidae. Based on the pres-ence of posterior processes composed of a mosaic of small pieces, Pawson & Fell (1965) transferred Thyoninae Panning to the family Phyllophoridae. No new species of Pentamera have been added to the west coast fauna since Deichmann (1938a, 1938b), with the exception of those trans-ferred to the genus by Panning (1949). The purpose of this paper is to describe two new species of Pentamera from the Pacific coast of North America and present a summary table of morphological characters for spe-cies from the west coast of North and South America. Materials and Methods Ossicle slides were prepared by the method described in Lambert (1985). At least 30 ossicles per specimen were mea-sured on transects across each slide. Length and width of disc, and width of central spire were recorded for tables. Length, height of curve, and height of spire were recorded for supporting tables (Fig. 7). Only ossicles that were totally within the field of vision, lying flat, and not broken, were measured. Via a drawing tube attached to a Wild M20 microscope, the image of each ossicle was visualised on a digitising tablet (Summas-ketch II, Summagraphics Corporation). Measurements were made with the cursor and automatically saved to a file using SigmaScan software (Jandel Scientific). That file was then transferred to a statistical package (Systat, Systat, Inc.) for analysis. External measurements of the whole spec-imen were made with an ocular micrometer, calipers, or in the case of strongly curved specimens, a string was used to trace the distance from the base of the tentacles to the anus, around the outer side of the curve, usually the ventral side. Institutions mentioned in this paper are abbreviated as follows: Allan Hancock
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