« Members of the Heterostropha; cone-shaped shell usually wider than high, with open umbilicus surrounded by a nodule-bearing spiral rib, sculpture of very regular spiral rings intersected by axial grooves or growth lines and, in most cases, a regular color pattern; shell circumference usually with 1 or 2 keels; columellar wall of shell aperture (“inner lip”) with grooves; smooth protoconch separated from the teleoconch by distinct peritreme, heterostrophic (placed “upside down”, with the axes of proto- and teleoconch diverging by less than 10°); first part of the initial teleoconch whorls with distinct growth marks; operculum corneous, built by spirally arranged lamellae, concave flat or cone-shaped, always with peg-projection on body side… » – R. Bieler: “Architectonicidae of the Indo-Pacific (Mollusca, Gastropoda)”, Abhandlungen des Naturwissenschaftlichen Vereins in Hamburg N.F.30, Stuttgart 1993, p.35-36.
 

The genus is monotypic. « Shell conical, depressed, with slightly convex whorls and a concave base; keel very marked. […] The sculpture of the shell is essentially spiral. Dorsally, the whorls are mostly smooth, except for two peripheral cords separated by a furrow, the outermost of which forming the keel. The base, concave, has a complex sculpture: the umbilicus, mediocre, is surrounded by a strongly crenulated periombilical cord; therefore, proceeding outwards, one encounters a deep furrow, a wide band with strong radial folds and a second deep furrow. The peripheral band of the base is decorated with 3-5 spiral cords separated by grooves. Colour of the shell yellowish brown; periostracum thin and transparent… » – Melone & Taviani: “Revisione delle Architectonicidae del Mediterraneo”, Lavori Società Italiana di Malacologia vol.21, Milano 1984 (1985), p.161.
 

Umbilicus with the crenae more flatten that in other genera; « whorls somewhat bulging, on either side of the peripheral keel distinctly concave; both sides usually with numerous spiral ribs or threads; juvenile whorls usually with distinct subsutural rib, 5-7 spiral ribs and distinct upper peripheral rib above the peripheral keel; later whorls with 6-10 spiral ribs between subsutural rib and upper peripheral rib (SSR and UPR then hardly stronger than other spiral ribs); 0-4 narrow spiral threads between UPR and keel-forming lower peripheral rib; spiral ribs nodose or almost smooth; upper point of whorl attachment at or below center of keel-forming rib; base: concave area near peripheral keel with 4-6 fine spiral ribs; convex basal area with about 10 spiral ribs, increasing in width towards umbilicus; 2-4 broad spiral ribs surrounding umbilicus, innermost of which (UC) broadest and flattened; umbilical wall with growth lines, without spiral ribs… » – R. Bieler: “Architectonicidae of the Indo-Pacific (Mollusca, Gastropoda), Abhandlungen des Naturwissenschaftlichen Vereins in Hamburg Bd.30, stuttgart 1993, p.129.
 

Shell small, with a more or less elevated spire and rounded whorls; sculpture granulose, variable in strength; suture impressed; operculum moderately to highly conical. The labial projections that give rise to keels in Architectonicidae are not situated, like in Basisulcata, at the abapical angle of the lip, but more in its middle; hence, the whorls are not angular but rounded (Heliacus cylindricus, Heliacus areola) to subquadrangular (Heliacus sterkii).
 

Shell small, with rounded whorls, a marked suture and a double peripheral keel; sculpture very weak, made of slight growth marks crossed by often slighter spiral striae; umbilicus narrower than in the other genera of the family.
 

shell minute, with a flat spire composed of quadrangular bicarinate whorls; umbilicus extremely wide. Sculpture made up of numerous thin radial growth marks crossed by weak spirals; sometimes, additional stronger spiral threads occur on the last whorl, between the two major keels.
 

shell similar to those of the genus Heliacus (syn. Torinia), but minute and always flat-spired. Also, on the sides of the last whorl, the spiral sculpture is stronger than it is in Heliacus.
 

shell small, with a flatten apical area; protoconch anastrophic; the whorls expand radially at the same ratio but increase more and more in heigh, giving the shell a domed appearance; presence of a very strong keel at the periphery; umbilicus wide.
 

shell minute, similar to those of the genus Pseudomalaxis but with the whorls usually more or less detached from each other (not at all in lamellifer, moderately in clenchi, completely in exornatus); the main difference with Pseudomalaxis is in the number and the position of the labial projections: they are 4 in number, one at each angle of the aperture (circular internally, quadrate externally).