Description.- Shell thick, subdiaphanous, about 70 mm in height, white in colour; spire with 12-14 whorls, flatly convex, protoconch usually eroded; surface with irregular spiral impressed striae, and very irregular thick, slightly oblique, low ribs, basal keel strong; aperture circular, peristome incomplete; umbilicus closed.
Discussion.- This is one of the confused species in Japan. Habe & Ito (1965) illustrated A ochotensis and A. costulata, and caused great confusion. Clench & Turner (1950) showed a syntype of A. borealis (Beck, 1842) and a lectotype of A. costulata (as a synonym of borealis) and found that this species was moderately small (<40 mm), but Habe & Ito’s (1965) illustration gave no dimensions and the magnified illustration of A costulata looks similar to A ochotensis which is in fact one of the largest species of this genus. A. ochotensis of Shikama (1964), Habe & Ito (1965) and Habe (1975) may be Cirsotrema (Boreoscala) matugisiense (Ozaki, 1956). Comparing Tryons (1887) illustrations of Scalaria ochotensis, S. costulata and Ozakis (1956) illustration of C (B.) matugisiense, these species in illustrations of Matsukuma et al. (1991) were totally confused: A. ochotensis in their studies is Cirsotrema (Boreoscala) matugisiense and A. costulata is A. ochotensis.
Type locality.- South coast of the Sea of Ochotsk
Material studied.- NA (off Wakkanai, Hokkaido, Japan, trawled at 50 m deep); WC (off Choshi, Boso Peninsula, Japan, trawled at 100 m deep)
Dimensions.- height 72.5 mm; breadth 20 mm , height 83 mm; breadth 23 mm
Distribution.- Off Hokkaido, Japan; the Sea of Ochotsk.