Protozoan microscopy. 19th century artwork of microscopic details of protozoan micro-organisms, seen under a microscope. These include a parasitic worm-like organism (Monocystis lumbricorum, upper left), foraminiferans and rotifers (one seen at lower centre). Artwork from the 1883 edition of Jabez Hogg's book The Microscope: its History, Construction and Application.