Orbitestella regina Kay, new species. Height, 0.5 mm; diameter, 2 mm. Shell: discoid; with a single beaded carina and transverse riblets; white. Spire: flat, apex sunken; protoconch of a single smooth whorl; teleoconch of two whorls. Sculpture: periphery of last whorl with a single, strong, beaded carina and with axial riblets crossing the whorl to the carina, about 26 across the last whorl. Aperture: subcircular, peristome continuous; outer lip thin, angled by the carina; umbilicus wide and deep. Color: white. These minute mollusks are common in tide pools and in sediments to depths of 50 m.
Type locality: Keahole Point, Hawaii. Holotype: Bernice P. Bishop Museum No. 9770. Paratypes: Australian Museum; British Museum (Natural History); U. S. National Museum. \
The shells of O. regina are distinguished from those of the type of the genus, O. bastowi (Gatliff, 1906) from Victoria, Australia, by the distinct transverse riblets. This species is named for Miss Regina Kawamoto who has picked hundreds of shells in this size range from sediments in her studies of micromollusks.
The orbitestellids have minute, discoid shells with the spire slightly raised or sunken, and a wide umbilicus. The aperture is quadrate, the dorsal part of the outer lip typically bent downward slightly in front of the posterior sinus. The operculum is circular and multispiral.