Katharina tunicata, is a primarily low intertidal (although it is sometimes found in the mid intertidal zone) chiton, commonly known as the Black Katy. The genus of the animal was named in honor of Lady Katherine Douglas who was responsible for sending specimens of the chiton to England in 1815 for description and examination. The body of the animal consists of eight white plates, which are often discolored to a dirty green-brown color. The plates are embedded in the girdle, which is evidently black and has a leather-like texture. The Black Katy can be found on rocky, generally shaded, beaches where it attaches it's muscular foot firmly to a secure (usually rocky) substrate. These animals are often found living on or near algae deposits. It is the algae that comprise their major food source and often cause the discoloration of the dorsal plates. K. tunicata is an ecologically important species that helps maintain algae and limpet populations.