LACUNA

(Lnt.) In Botany, a term applied in describing lichens, to denote one of the small hollows or pits on the ii|>|ier surface of the thallus. Also a name given occasionally to the internal organ, commonly called an aircell, lying in the midst of the cellular ti ue of plants. LACtrNAR. (Lat.) In Architecture, the ceiling or under surface of the member of an order. Also the under side of the larmier or corona of a cornice. The under side also of that part of the architrave between the capitals of columns. The ceiling of any part in architecture only receive.-,the name of lacunar when it consists of compartments sunk or hollowed without spaces or bands between the panels: if it is with bands, it is called laquear. [s. 651]