TYPE LOCALITY. — Moeshima, Kagoshima Bay, Japan (Pleistocene).

MATERIAL EXAMINED. - Indonesia. KARUBAR: stn DW 28, Kai Islands, 05°3rS, 132°54'E, 448-467 m, 1 dd; stn CP 38, Tanim-bar Islands, 07°40'S, 132°27'E, 620-666 m, 1 dd (Figs 1A, B).


DISTRIBUTION. - Reported from Tosa and Kagoshima Bays, Japan, in 100-200 m (Hori 2000a). Material herein collected in Indonesia (Fig. 3), in 467-620 m.

DESCRIPTION. — Shell morphology* Length 16 mm, width 9 mm (largest specimen examined). Shell solid, elongate, with almost parallel sides. Body whorl large; spire short, conical, with 4 whorls. Suture slightly channeled. Protoconch unknown. Umbilicus closed. Aperture wider anteriorly and narrower posteriorly, about 6/7 of the body whorl length. Columellar margin thickened, slightly oblique, with a small, simple fold. Sculpture of a number of punctuated spiral grooves. The punctuations are conspicuous, irregular, almost rectangular, and situated next to each other within each groove. The grooves are separated by gaps narrower than the grooves. Colour uniformly brownish.
Anatomy. Unknown. All shells collected lacked soft parts.

REMARKS. — The two shells here examined, collected from Indonesia, resemble the holotype of A. nakayamai, illustrated by Higo et al (2001). The outline of the shell, sculpture, shape of the aperture and other conchological characters are very similar to those of the holotype. Therefore the material from Indonesia is tentatively assigned to A. nakayamai until more specimens from this region become available to allow a reliable comparison and positive identification.
Acteon nakayamai was originally described by Habe (1952a) based on Pleistocene material collected from Moeshima, Kagoshima Bay, Kyushu, Japan. Subsequently Habe (1961) transferred it to the genus Punctacteon Habe, 1961. A definitive generic placement for this species is not possible until complete specimens become available for study, and it is provisionally regarded as a member of Acteon, the genus to which it was originally assigned.