Alia permodesta: Astyris permodesta: Alia permodesta: Shell small, thin, polished,with live rounded whorls, a pale yellowish epidermis covering a bluish white substratum; transverse sculpture only of faint incremental lines; spiral sculpture of fine spiral threads on the base of the shell, obsolete or absent between the sutures; aperture wide, oval; outer lip thin, simple, very slightly reflected ;axis pervious; canal wide, extremely short, hardly differentiated; pillar smooth, twisted, not callous; suture distinct, not appressed or channeled; nucleus rounded, slightly flattened, generally eroded. Maximum longitude of shell, 11 mm; maximum latitude. 7mm.

Alia permodesta: Astyris permodesta: Description. Shell to 14 mm long, broadly inflated, thin, off-white under greenish brown periostracum, but often coated with dark brown mineral deposits; apex decollate and plugged, leaving just 3-3.5 whorls; sculpture lacking except for weak spiral cords on base of shell. Lip thin, lacking lirae; columella simple, siphonal canal wide open.
Distribution. Cape Foulweather, Lincoln County, Oregon, to San Diego, San Diego County, California. Soft bottoms with cold seeps, whale carcasses, and anoxic greenish gray mud, 500-1900 m. Common.
Remarks. The species is characteristic of anoxic bottoms of offshore basins. Several of the recorded localities include cold seeps, and it is also a common inhabitant of whale bone in deep water (Smith et al. 1989), where it occurs along with species of large vesicomyid bivalves and other characteristic inhabitants of reducing environments.
The generic assignment is based on the thin lip without lirae; it may prove to be unrelated. It differs from Mitrella gausapata in lacking the lirae and in having a thinner and broader shell. A very similar species Astyris atacamensis Araya, Catalan & Aliaga, 2016) has recently been named from anoxic deep water habitats off Chile.

Alia permodesta: Astyris permodesta: Alia permodesta: USA, off the Santa Barbara Islands, California, in 270 fathoms, mud.