These cells are enclosed in a rigid, shell-like envelope, made up of minerals and polysaccharide mucilage, with a defined collar or truncate extension that surrounds an anterior apical pore where the flagellum emerges from, also known as a lorica.
These cells are enveloped in a sturdy, protective covering composed of minerals and polysaccharide mucus, featuring a distinct collar or truncated protrusion surrounding an anterior axial opening through which the flagellum emerges, also referred to as a lorica.