Moraxella lacunata is a rod-shaped,[1] Gram-negative, nonmotile bacterium, generally present as diploid pairs.

[2] It causes one of the commonest forms of catarrhal conjunctivitis.

[3] Moraxella lacunata was first described independently by Victor Morax (1896) and Theodor Axenfeld (1897), hence the alternate name "Morax-Axenfeld diplobacilli" and the name of eye infection in humans is sometimes called Morax-Axenfeld conjunctivitis.

M. lacunata became shorter and tended to lose its Gram-negative staining characteristic when left out for 5 days.

It also tended to retain these new characteristics on subsequent blood-agar transfers.