Metaxia brunnicephala Kay, new species. Length, 3 mm; diameter, 0.75 mm. Shell: conical; narrow, dextrally coiled and with a cerithiopsidlike aperture; four beaded spirals on each whorl; white, protoconch dark brown. Spire: protoconch of four dark brown, conical whorls, the apical with microscopic rippled threads, the other whorls with a single spiral carina and axial threads; teleoconch of seven convex whorls; suture deeply impressed. Sculpture: spiral sculpture of four beaded threads, apical threads least prominent and becoming obsolete on the later whorls; a fifth cord on the base of the last whorl; interspaces between the spirals reticulated by numerous fine axial threads; axial sculpture of strong threads which override the spirals, breaking them into distinct tubercles. Aperture: subquadrate; base excavate; outer lip thin; anterior canal widely notched. Color: white, protoconch dark brown. These right-handed triphorids are occasionally found in beach drift and in sediments to depths of 30 m. Shells are variable in length and occasionally may be streaked with red-brown.
Type locality: Poipu Beach, Kauai, in beach drift. Holotype: Bernice P. Bishop Museum No. 9782. Paratypes: U. S. National Museum.
These shells are distinguished by their tall, sculptured protoconch from those of M. albicephala from Hawaii and M. kermadecensis Marshall, 1977, from New Zealand. Although similar in sculpture and features of the protoconch to the shells of M. exaltata (Powell, 1930), from New Zealand, the teleoconch in that species is light, translucent brownish-yellow, mottled with red-brown axial streaks (Marshall, 1977). Derivation of name: brun, Anglo-Saxon — brown; kephale, Greek — head. Refers to the brown protoconch.