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A new species of echinoderid kinorhynch, Echinoderes sensibilis, is described and illustrated using light and electron microscopy. The specimens were collected from masses of the red algae Corallina pilulifera growing in intertidal pools in Tanabe Bay, Honshu Island, Japan. Diagnostic characters of E. sensibilis include the presence of middorsal spines on segments 6-10; lateral spines/tubules on segments 4, 7-12; remarkable trapezium-like subventral fields of minute cuticular hairs on segments 5-12. The positions of numerous sensory spots, large sieve areas, glandular tubes and the shape of terminal tergal and sternal extensions are also diagnostic. All taxonomic characters used for this description are illustrated by SEM. Echinoderes sensibilis constitutes the fifty-eight valid species of the genus Echinoderes and the fourteenth species described from the Pacific Ocean. This is the third representative of Pacific kinorhynchs found only in the intertidal zone and the first Pacific Echinoderes living on red macroalgae in intertidal pools.

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Larvae of priapulids are characterized by radial symmetry evident from both external and internal characters of the introvert and lorica. The bilaterality appears as a result of a combination of several radial symmetries: pentaradial symmetry of the teeth, octaradial symmetry of the primary scalids, 25-radial symmetry of scalids, biradial symmetry of the neck, and biradial and decaradial symmetry of the trunk. Internal radiality is exhibited by musculature and the circumpharyngeal nerve ring. Internal bilaterality is evident from the position of the ventral nerve cord and excretory elements. Externally, the bilaterality is determined by the position of the anal tubulus and two shortened midventral rows of scalids bordering the ventral nerve cord. The lorical elements define the biradial symmetry that is missing in adult priapulids. The radial symmetry of larvae is a secondary appearance considered an evolutionary adaptation to a lifestyle within the three-dimensional environment of the benthic sediment.

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A new species of echinoderid kinorhynch, Echinoderes aureus, is described and illustrated using a differential interference contrast microscope with Nomarski optics. The kinorhynchs were collected from washings of a brown alga, Padina arborescens Holmes, growing in tide pools in Tanabe Bay, Honshu Island, Japan. Diagnostic characters of E. aureLts are the presence of middorsal spines on segments 6-10, lateral spines/tubu}es on seg-ments4 and 7-12, a pair of remarkably large subcuticular scars in a subventral position on segment 3, and an ineomplete rnidventral articulation on segment 4. The positions of numerous sensory-glandular organs, the sizes of various lateral spinesltubules, and the shapes of the terminal tergal and sternal extensions are also diagnostic. Echinoderes aureus constitutes the 59th valid species o ± ' the genus Echinoderes and the 15th speeies described from the Pacific Ocean. This is the fourth representative of Pacific kinorhynchs found only in the intertidal zone and the second Pacific Ebhinoderes living on macroalgae in tide pools, A dichotomous key to all 59 species is provided.