Acanthometra (Acantharea, Acantharia). Illustration shows marine animals. Kunstformen der Natur (Art Forms in Nature) is a book of lithographic and halftone prints by Ernst Haeckel. It consists of 100 prints of various organisms, many of which were first described by Haeckel himself, translated from sketch to print by lithographer Adolf Giltsch. Ernst Haeckel (1834 - 1919) was a German biologist, naturalist, philosopher, physician, professor, marine biologist, and artist. Haeckel's identification key was not provided.