|Architectonicidae, the sundials, have wide, low, conic-shaped shells, usually with a small aperture opening to the side. The shells usually have spirally grooves or ridges, granulations or both. Their umbilicus, the depression underneath the shell, is usually wide and goes deep within the shell. Sundials bury into the substrate, usually in subtidal areas, and come out only at night to feed or spawn. They are sometimes found under rocks and corals. Their primary diet is anemones and other related organisms (jellyfishes, corals, etc.). There are 3 species found in Texas.