Description. Shell white, medium to large, up to 10 whorls; costae 14-21 per whorl, strong, with pronounced shoulder spine, producing tabulate profile, costae often broad and fused with those behind. Length 15-24 mm.
Type Locality and Type Specimens. Santa Catalina Island, California, 16 fathoms. Lectotype (here designated): USNM 109309. Epitonium acrostephanus: Newport, Orange County, California; lectotype (here designated): USNM 110638. Epitonium catalinae: Santa Catalina Island, California, 16 fathoms; holotype USNM 198628. Epitonium tabulatum: Islas Coronados, Baja California, 16 fathoms; holotype: USNM 109569. Epitonium regum: Point Reyes, Marin County, California, 61 fathoms; holotype: USNM 206576. Material Examined. California: Santa Maria Basin, Phase I, sta. 42,100 m (1); Phase II, sta. R-l, 91 m (3); sta. R-4, 92 m (1); sta. R-8,90 m (1). Other material: 340 lots in the LACM collection.
Distribution. British Columbia (54°N), to Bahia Magdalena, Baja California Sur (24°N) (DuShane, 1979:116).
Habitat. 18-360 m on soft bottoms (DuShane, 1979:116).
Remarks. This species is characterized by its deep suture and tabulate aspect produced by the spinose costae that are often folded back. The suture is deeper than that of E. berryi.
Changes are made here to the synonymy of this species given by DuShane (1979:115): Epitonium catalinae Dall, 1908, is added to the synonymy, and E. berryi and E. rectilaminatum, both Dall, 1907, are removed.

As E. acrostephanus:
Shell slender, acute, turrited, with two nuclear and nine or more subsequent whorls which are in contact, though separated by a deep suture across which the varices are continuous; axial sculpture of (on the last whorl 14) nearly vertical, thin, sharp, slightly re- flected varices, which are expanded near the suture into a small lamella of which the posterior corner, when intact, bears a small sharp spine, behind which the varix is much attenuated and turns into the suture, which it crosses and becomes connected with one of the varices of the preceding whorl; the anterior face of the varices is concentrically sharply striate, and the portion which approaches. the center of the base is slightly flattened, although there is no basal disk or perforation; the space between the varices is smooth and polished, but under a lens shows traces of faint spiral striation, more or less irregular; the aperture is rounded-ovate, the peritreme thin and like the preceding varices; the operculum is thin, of about three whorls, concave and centrifugally striated, of a pale horn color. Height of shell, 20; of last whorl, 8.5: of peritreme, 4.5; maximum diameter, 6.5 mm. Type. Cat. No. 110638, U.S.N.M. Range from Monterey, California, south to the Coronado Islands near San Diego. It has been dredged in depths from 16 to 34 fathoms. The type-specimen was collected by Mr, H. N. Lowe, who dredged it at Newport, California. This is a not uncommon species in the dredgings, though usually smaller than the dimensions given above. It may be distinguished from E. subcoronatum Carpenter by its more crowded, higher and minutely lamellose or striated varices which from the posterior expansion give the whorls a tabulate appearance.

As E. catalinae:
Shell slender, white, turrited, imperforate, with more than seven adherent whorls: nucleus (lost); suture distinct, closed: varices (on the last whorl 14) continuous, making nearly one revolution around the axis in ascending the spire; they are flatly reflected, axially striate, subspinose at the shoulder, giving a tabulate aspect to the rounded whorls. There is no basal disk on the whorl, but on the basal part of each reflection of the varices there is a smooth area over which the suture travels, and which, taken collectively, gives the effect of segments of a disk imposed on the varices but not on the whorl: below the shoulder the varices are widely reflected, extending for a space to the angle of reflection of the preceding varix, where it would seem these extensions are normally attached, covering a hollow space between them and the whorl, but in the type-specimen most of these extensions are broken away: aperture subcircular. Height of (decollate) six whorls, 12.0; of last whorl, 6.0; of aperture, 2.7; maximum diameter, 4.5 mm. Type. Cat. No. 198628, U.S.N.M. Off the south side of Catalina Island, California, in 16 fathoms, mud, near the entrance to the small harbor: W. H. Dall. This is a very interesting species, which if perfect might have, from the fusion of the varices, much the aspect of a Cirsotrema.