Shells minute to small, with a semilunar aperture, rounded at the base, angular adapically; presence of an operculum. Umbilicus absent or reduced to a simple slit.
 

Shell minute, rounded, ovate-conical; the sculpture exhibits a combination of radial and spiral cords that often results in the appearance of nodules at their intersections. With the exception of few species like A. carinata in which spirals predominate, or A. maximilicutiani, the shell of which is mainly sculptured by the radials, usually radials and spirals are of almost equal strength.
 

Shell minute, translucent. Protoconch subplanorbiform and bicarinate. Teleoconch with convex whorls and a marked suture, an aperture devoid of notch, an umbilical slit. Sculpture of radial costae often obsolete, sometimes crossed by weaker spiral striae. The genus lives in deep water.
 

« Shell minute, coiled, smooth, tall-spired, with pyriform aperture and dome-shaped protoconch. Operculum thin, simple, with eccentric nucleus. » – W. Ponder: “A gravel beach shelled micro-gastropod assemblage from Ceuta”, Bulletin du Muséum National d’Histoire Naturelle ser.4, vol.12, section A, Paris 1990, p.303. The shell is more cylindrical, less tapering than in Peringiella.
 

« Shell: minute to small, elongate-conic to ovate-conic, non-umbilicate, with subobsolete spiral sculpture to spiral keels; axial sculpture: weak riblets or growth lines. Aperture with simple peristome, angled posteriorly, outer lip with or without varix, prosocline to orthocline. Protoconch paucispiral, with spiral striae or with spiral lirae having axial micro-lamellae between. » – W. Ponder: “A review of the genera of the Rissoidae”, Records of the Australian Museum suppl.4, Sydney 1984, p.52.
 

« The new name Crisilla can be used to distinguish this group entirely composed of semi-striate, exquisite, blond, more or less vivid forms with darker blotches on the suture and at the periphery. » – T. A. di Monterosato: “Molluschi viventi e quaternari raccolti lungo le coste della Tripolitania”, Bollettino della Società Zoologica Italiana ser.3 vol.4, Roma 1917, p.12. « Outer lip without varix and internal denticles […]. Protoconch micro sculpture with spiral elements very weak, pustules small. » – W. Ponder: “A review of the genera of the Rissoidae”, Records of the Australian Museum suppl.4, Sydney 1984, p.43.
 

« Shell: minute to small, ovate-conic, non-umbilicate, usually with strong axial ribs (weak to absent on base), crossed by spiral cords or spiral cords predominate; axial ribs rarely absent; a few spiral cords prominent on base. Aperture oval, […] rounded anteriorly, with varix on opisthocline outer lip; peristome duplicated. Protoconch multispiral or paucispiral; if muitispiral with netted microsculpture, if paucispiral with gemmate or smooth spiral keels; apex usually strongly tilted. » – W. Ponder: “A review of the genera of the Rissoidae”, Records of the Australian Museum suppl.4, Sydney 1984, p.46.
 

« Size very small; form of Setia; spire short, smooth or very finely striated; umbilicus circumscribed but very narrow; no basal streaks. Aperture rounded, with continuous peristome; labrum thickened, slightly tilted; columella poorly excavated, with external edge well detached from the umbilical region on which the columellar border does not overturn. » – M. Cossmann: Essais de paléoconchologie comparée vol.XII, Paris 1921, p.43.
 

« Shell: minute to small, ovate-conic to elongate-ovate, non-umbilicate to narrowly umbilicate, smooth or with weak to strong spiral sculpture, sometimes with a few spiral keels. Axial sculpture usually rather weak to very weak; sometimes axial ribs present but do not extend over base; sculpture rarely clathrate. Aperture with simple peristome, oval, weakly angled and channelled posteriorly, simple and rounded anteriorly; outer lip opisthocline, varix weak to heavy. Protoconch dome-shaped, sometimes with 1 or more spiral keels; smooth […] or with microsculpture of granules, anastomosing or spirally aligned raised threads or, sometimes, wavy, spirally arranged rows of granules. » – W. Ponder: “A review of the genera of the Rissoidae”, Records of the Australian Museum suppl.4, Sydney 1984, p.54-55.
 

« Shell: minute to small, elongate-conic, non-umbilicate, smooth, not glossy. Aperture with simple peristome, angled and weakly notched posteriorly, rounded anteriorly. Outer lip more or less orthocline, with weak to strong varix and weak denticles internally in type-species. Protoconch smooth or exceedingly minutely and shallowly pitted, dome-shaped, paucispiral. » – W. Ponder: “A review of the genera of the Rissoidae”, Records of the Australian Museum suppl.4, Sydney 1984, p.62. Similar in shape to Botryphallus but with a less obtuse apical area.
 

« Section with turriculated whorls ans interrupted costae; lip acute, not enlarged exteriorly. » – T. A. di Monterosato: Nomenclatura generica e specifica di alcune conchiglie mediterranee, Palermo 1884, p.56. – « Shell: minute to small, ovate to conic, non-umbilicate to umbilicate, smooth or, typically, with axial ribs stronger than spiral sculpture; axial ribs usually obsolete on base. Aperture with simple peristome, inner lip narrow, attached to parietal wall, angled posteriorly, anterior end rounded, simple. Outer lip opisthocline to prosocline, with or without external varix. Protoconch of 1½ to 2¼ whorls, smooth or with spiral threads or spiral rows of minute, closely spaced pustules. » – W. Ponder: “A review of the genera of the Rissoidae”, Records of the Australian Museum suppl.4, Sydney 1984, p.26.
 

Shell small, « elongate-conic, non-umbilicate; axial sculpture usually predominant, usually of prominent, broad ribs. Weak spiral threads often present, sometimes broad with spaces between them sunken to form shallow pits. Sculpture weak to moderately strong axial ribs; spiral cords weak, low, usually do not cross axial ribs; axials not terminated at periphery by a spiral cord but usually weak or absent on base; sometimes smooth. Aperture with shallow posterior sinus broadly rounded anteriorly; columella often thick, sometimes twisted. Outer lip opisthocline to prosocline, with weak to pronounced varix externally […]. Protoconch narrowly conic, edge sinuate, usually more than two whorls. Prodissoconch usually small, slightly tilted, sometimes sculptured with a few, very weak spiral threads which disappear before commencement of second whorl; otherwise smooth. » – W. Ponder: “A review of the genera of the Rissoidae”, Records of the Australian Museum suppl.4, Sydney 1984, p.21.
 

The shell is tall and slender, with a long last whorl and very developed apertural margins.
 

« Shell: minute, ovate to ovate-conic, whorls convex; aperture with simple peristome, with posterior angulation but lacking distinct anterior and posterior channels; outer lip prosocline, with or without weak external varix; surface smooth or with weak to moderate spiral threads and axial growth lines. Protoconch dome-shaped, of about 1¼ -1½ whorls, first 1½ whorl very large; surface either smooth, except for weak spiral threads on last ¾ whorl, or with spiral rows of minute gemmae. » – W. Ponder: “A review of the genera of the Rissoidae”, Records of the Australian Museum suppl.4, Sydney 1984, p.33.