Architectonica perspectiva
Architectonica perspectiva, whose common name is the clear or perspective sundial shell, is a species of sea snail, a marine gastropod mollusk in the family Architectonicidae, which are known as the staircase shells or sundials.
;Subspecies and variety:Architectonica perspectiva fressa Iredale, 1936: synonym of Architectonica perspectiva Architectonica perspectiva var. modesta : synonym of ''Architectonica modesta''
Description
The shell is orbiculato-conical, in other words it is essentially a low, depressed cone with a rounded base. The shell is smooth, and adorned with soot-brown coloration. The lower whorls are smooth and somewhat swollen, while the upper whorls are longitudinally folded. The median area is pale and is painted with broad, oblique brown stripes. It is keeled at the periphery. Above the keel, there is a narrow, flattened area articulated with quadrate brown spots. The base is slightly swollen, pale, and smooth. The aperture is quadrate. The umbilicus is wide-open and is furnished with straight brown crenations.The snails have a shell 5 to 7 centimeters in diameter. The cone-like shell coils up from a flat base. The spirals are composed of vibrant shades of black, white, and brown. The body and its tentacles are striped as well to match the shell. Its operculum is made of a horn-like material.