As noted under the description of the genus, the most distinctive characters of Distorsomina pusilla are its small size (up to 12.5 mm high - the smallest species of tonnoidean I am aware of), its very narrow shape compared with species of Personopsis. in particular, and its small, very narrow aperture in which the typical personid row of enlarged basal columellar nodules is located obliquely and relatively adapically. occupying the mid-columellar area of the inner lip of the very small aperture. Part of the unusual appearance of the aperture of D. pusilla results from the relatively large size of this row of nodules compared with the rest of the aperture; the relatively high, adapical position of this nodule row could result largely from the small maximum shell size. The base of the inner part of the columellar lip (i.e.. just visible well inside the aperture) is expanded to form a distinctive, thin, sharp-edged ridge, margining the columella and sharply demarcating the narrow channel curving around into the anterior siphonal canal. The protoconch consists of 2.3-2.5 evenly convex whorls, forming a typical "primitive ranellid" (i.e.. plesiomorphic) low-turbiniform protoconch with an apparently smooth surface; a juvenile collected alive by EXPEDITION MONTROUZIER bears two rows of low periostracal flanges on the protoconch. and is only the second personid protoconch I have seen with an obvious constriction between protoconchs I and II (one was figured earlier, in Distorsio euconstricta. by BEU (1987: fig. 139) but it has not been seen on other Distorsio protoconchs). The single Indian Ocean specimen I have seen (off Mayotte. in 15-20 m, MNHN) is expanded a little more widely between varices than most western Pacific specimens, but is matched by the most extreme western Pacific specimens. DIMENSIONS. — Holotype: H 9.9, D 5.3. - Amami-Oshima Islands, southern Japan. Melvill-Tomlin Collection, National Museum of Wales, largest specimen seen: H 12.5. D 6.9.
DISTRIBUTION. — Although Distorsomina pusilla is uncommon in collections, and its range has been poorly known until recently, the locality data collected above indicate that it ranges throughout the Indo-West Pacific Province, from the western Indian Ocean (Comores Islands) and from southern Kyushu. Japan, south to Queensland. New Caledonia and the Coral Sea, and eastwards throughout Micronesia, Melanesia and Polynesia to Hawaii. The first Indian Ocean record is listed above, but others confidently can be expected. Living specimens have been collected in New Caledonia in 12-57 m.

Distorsio pusilla Pease, 1861a. Length, 10 mm; diameter, 5 mm. Shell: conic-ovate; somewhat distorted; with axial ribs and nodulose spiral cords; cream to light brown. Spire: teleoconch of four or five slightly convex, twisted whorls; suture impressed. Sculpture: about seven varices, most prominent on the last whorl; relatively strong axial ribs (15 on the last whorl) crossed by nodulose spiral cords; additional cords on the siphonal fasciole; interspaces finely cancellate. Aperture: narrow, occluded by seven prominent denticles on the outer lip and four columellar folds. Color: cream to light brown. This cymatiid is rarely found, known only from occasional beachwom shells and an occasional specimen found at depths of more than 30 m. D. pusilla was described from the Hawaiian Islands and has also been reported from Guam (Cernohorsky, 1975b).