Large, moderately depressed cone-shaped shell with moderately wide umbilicus; whorls on upper side gemmate, somewhat inflated; two spiral grooves below suture (midrib-area divided subequally, with upper midrib narrower); ± wide groove at base of the lower midrib. Subsutural rib whitish with pattern of ± large brown blotches (usually not extending onto midrib-area); basal field with 1-5 dotted spiral lines, proxumbical rib whitish (often with a few darker marks), umbilical crenae whitish or reddish brown. Protoconch diameter < 1.38 mm.
Teleoconch: Large, diameter of specimens in collections usually 30-40 (rarely over 50) at 5 1/2 to 6 1/2 (7 1/4)) whorls; ranging from rather thin- to thick-walled. Shape: moderately depressed cone-shaped, with whorls somewhat inflated (especially on upper side); umbilicus moderately wide (UD ca. 24% of SD). Sculpture: as in A. purpurata. Coloration: SSR initially white, with pattern of brown blotches (ca. 9-15 per whorl, each 1-4 nodules wide), starting at about 3 Tw; blotches usually not extending onto UMR; UMR initially purplish-brown, turning tan as LMR after about 3 Tw; UPR, LPR and IPR whitish with dark-brown blotches; BF flamed with shades of mauve and tan, with 1-5 spiral lines of brown blotches of various widths in front of PUR; PUR white or whitish-brown with a few darker marks; UC whitish or reddish-brown. - Protoconch: large to very large (1.38-1.78, x = 1.54); distinctly heterostrophic; often with ridge in anal-keel area; light- to dark-brown, with darker outer corner in front of varix. - Operculum: as described for genus. -Radula and Anatomy: not known.

Shell shape and sculpture of Architectonica stellata agree with those of A. purpurata. The coloration of the midrib-area is different: in A. stellata, blotches of the subsutural-rib do not usually extend onto the upper midrib; if so, they are irregular in shape and do not fully correspond between the two ribs. A. stellata lacks the reddish-brown flames that occur on the base of most A. purpurata specimens. The protoconch-size is much larger than in A. purpurata , and there are significant statistical differences between the two in relative shell height (A. purpurata being higher-spired) and in relative umbilical diameter (A purpurata having a slightly smaller umbilicus) (see BIELER, 1984d).

Young specimens of the much larger-shelled Architectonica maxima can be distinguished by a wider groove at the base of the lower midrib, and by a much darker coloration of the proxumbical rib. Architectonica gualtierii is superficially similar, but has the midrib-area usually divided into two almost equally strong spiral ribs, has a much coarser sculpture and a brown-colored proxumbical rib.

Geographical distribution: Known from the northern Indian Ocean and Indonesia.
Habitat: Sublittoral (depth records from 45 to 285 m).