Shell with somewhat rounded whorls, which are often irregularly turned,sometimes with a row of nodules on the periphery, sculptured with finer and coarser revolving ridges, which are crossed by rather faint longitudinal ribs; outer lip heavy, toothed or strongly ridged within; columellar area strongly wrinkled, ridged; canal moderate, usually reflexed. Color tawny to dark brown, usually more or less white banded, sometimes having longitudinal dark flames; aperture varying from tawny to deep red or red brown, the teeth and folds whitish. The ground of the upper part of the inner lip is often blackish.
Length, 130; diameter, 55 mm.

Shell moderately large, reaching l38 mm. (about 5,5 inches) in length, solid, imperforate and strongly sculptured. Color, in specimens denuded of their periostracum. a grayish brown to golden brown, generally banded with alternating light and dark bands, particularly on the varices. Within the aperture the color on the outer lip is reddish-brown with 12 to 14 whitish plicae which are often paired. Parietal wall a dark chocolate in color, with numerous fine, irregular, white lamellae. Post-embryonic whorls seven and strongly convex. Spire moderately extended and produced at an angle of 45°. Aperture elliptical with the outer lip greatly thickened when a varix is produced. Parietal lip glazed and with numerous irregular lamellae. Siphonal canal short and generally curved upward. Columella arched inwardly with its base continuing into the parietal margin of the siphonal canal. Suture slightly indented. Sculpture consisting of numerous spiral and generally nodulose cords of unequal strength. Axial sculpture consisting of 3 to 5 strongly knobbed varices. Periostracum generally a light golden brown in color, roughened with numerous periostracal 'hairs’ and axial blades. Operculum unguiculate with a marginal nucleus and sculptured with numerous concentric growth ridges. Embryonic whorls four, slightly convex, amber in color and with very tine, axial striae.

Monoplex pilearis pilearis: 100mm. Thick, heavy, elongate-ovate, high spired, with rounded whorls, deep sutures; short, broad, recurved siphonal canal; aperture narrow. Coarse spiral cords, the uppermost strongly or weakly nodulous, deeply grooved between cords, nodules sinuously aligned axially; 3 pronounced varices. Crowded, paired teeth correspond to paired lirae in aperture; columella lirate throughout its length. Shades of brown variegated with white spiral bands; teeth and lirae white, the aperture red. Brown periostracum. Habitat: intertidal rock pools and offshore.

Cymatium (Septa) pileare (Linnaeus, 1758). (Synonym: Cymatium vestitum insulare Pilsbry, 1921.) Length, 41 mm; diameter, 20 mm. Shell: fusiform-turreted; spire equal in length to aperture and siphonal canal; with granular spiral cords and prominent varices; red-brown banded with white, columella with white and black lirae extending into the aperture. Spire: protoconch of six narrow, conical, olive-brown whorls; spire of teleoconch moderately extended and acute; whorls con- vex, depressed apically; suture shallow. Sculpture: six to seven prominent, beaded varices between which are three to five granular axial ribs of lesser diameter and weakly beaded spiral cords. Aperture: ovate, outer lip thick, denticles extending as lirae into the aperture; columella and parietal wall plicate. Color: yellow-white, often banded with darker yellow; aperture orange-brown or orange-red with white denticles; parietal wall dark brown, plicae white. These tritons are uncommon in shallow water but are frequent in dredge hauls at depths of 16 to 50 m off leeward Oahu. C. pileare has not been recorded from the leeward islands. C. pileare is circumtropical in distribution, found throughout the Indo-West Pacific, in the Atlantic from South Carolina to Texas, Brazil, and Bermuda, and in the eastern Pacific from the Gulf of California to Panama (Abbott, 1974). The Hawaiian shells are smaller than those found elsewhere in the Pacific: average length of the Hawaiian shells is 41 mm, average length of shells from other Pacific Islands is 69 mm.