cassididæ

from The Century Dictionary.

• In entomology, a family of phytophagous tetramerous Coleoptera or beetles, having a rounded body, whence the name of the group, Cyclica, in which they were formerly ranged.
• In conchology, a group of gastropod mollusks, typified by the genus Cassis, formerly referred to the Buccinidæ, now forming a separate family; the helmet-shells, or cameos.