Moelleriopsis BUSH, 1897:137. Type species, by monotypy, M. abyssicola BUSH, 1897 off northeastern United States, 3200 m.
Abyssogyra CLARKE, 1961 :352. Type species, by original designation, A. vemae CLARKE, 1961 , abyssal, southern Atlantic (new synonym).

Diagnosis. Small, skeneimorph gastropods with depressed spire, smooth except for three to six strong periumbilical keels. Aperture almost round. Protoconch with numerous distinct spiral lines. First teleoconch whorl adapically with deep and channelled suture. Radula (4 to 6) - 2 - 1 - 2 - (4 to 6). Central and lateral teeth thin and membranaceous. Operculum stiff and corneous.
Remarks. This generic name has hardly been used since it was introduced by BUSH. It was overlooked by THIELE (1929), WENZ (1938-44) and BROOKES KNIGHT & al. (1960).
I figure the holotype of the type species which is a badly broken shell .
I also figure the shell and radula of an undescribed species from the Indian Ocean, which is unquestionably referable to Moelleriopsis, to show in more detail the characteristics and the variation of the group). I have examined several other species from deep water off Europe and B. MARSHALL (pers. comm.) has recognised numerous similar species from off New Zealand.
Abyssogyra CLARKE, 1961 was based on A. vemae, a species similar to M. messanensis though more widely umbilicate .


Characteristics of Moelleriopsis are the larval shell with distinct spiral ribs and a varix separating it from the teleoconch, the strongly chanelled early suture, a single strong rib on the early teleoconch, which often soon disappears, and the strong keels inside and surrounding the umbilicus. The operculum is multispiral, corneous with short growth zone and cannot be retracted (or only very shortly) into the aperture. The radula is thin and membranaceous with the formula (4 to 6) - 2 - 1 - 2 - (4 to 6). The central tooth is thin and membranaceous with a triangular base and poorly, developed anterior supporting ridges. The apical part is drawn out into a long, tongue-like, deeply serrated flap. The first lateral tooth is membranaceous and triangular, with its inner, tip drawn out to a tongue-like serrated flap. The second lateral tooth is claw-like and 1/3 longer than the marginals, with a rather stout, flat tened base, and a large, smooth, distal cusp. The marginal teeth are claw-like, united basally, and equipped with a small basal plate. The outer part of the teeth has a comb¬like denticulation along the distal 1/4.