Shell minute, thin, fragile, rose in colour, rounded ovate; surface glossy, only with weak concentric striae; anterior dorsal margin shorter than the posterior; umbo rather large, prominent; lunule very weakly marked and cordate; interior of the ventral margin smooth and entire ; muscular scars and pallial impression are very obscure; in the right valve, the cardinal teeth three in number, of which the anterior two are parallel horizontally; in the left valve, a large V-shaped cardinal and a small cardinal behind it are present.
Length 2.4mm., height 2.3m., breadth 0.8 mm. (right valve) (figured type specimen collected by Mr. Yasutaka Nakayama).
Type locality ; Moeshima in the Kagoshima Bay, Kyushu (Pleisto¬cene deposits)
Remarks: Kelliella pacifica (Smith) is closely allied to this new fossil species, but is larger in size, white in colour and more round in shape.