Labyrinthodon
Lab`y*rin"tho*don\, n. [Gr. laby`rinqos labyrinth + 'odoy`s, 'odo`ntos, tooth.] (Paleon.) A genus of very large fossil amphibians, of the Triassic period, having bony plates on the under side of the body. It is the type of the order Labyrinthodonta. Called also {Mastodonsaurus}.