Cyphella are small depressions or cavity like openings into the medulla on the ventral surface of the thallus of certain lichens. They perform respiratory functions.
Viruses are not the only submicroscopic bodies capable of causing disorders within cells.
Sub-viral particles are infectious agents that bear a resemblance to viruses in structure and composition. But they are notably smaller and simpler than viruses but lack either nucleic acid or protein and are thus not viruses. (Thus they may be proteins beyond nucleic acids or only nucleic acids beyond protein coat /capsid.)