From Today in Science History:
Elliott Coues (Born 9 Sep 1842; died 25 Dec 1899). American army surgeon and ornithologist whose Key to North American Birds (1872) was the first work of its kind to present a taxonomic classification of birds according to an artificial key and promoted the systematic study of North American [birds]. Beginning the U.S. army as a medical cadet during the Civil War (1862), he became an assistant surgeon (1864-81). His interest in the study of birds began while a boy. He met many naturalists at the Smithsonian Institution and published his first technical paper at age 19. As his army assignments took him to various locations throughout the West, he continued studying the bird life in each new area, and found new species. He also did valuable work in mammalogy and wrote a book, Fur-Bearing Animals (1877).
Joseph Leidy (Born 9 Sep 1823; died 30 Apr 1891). American zoologist, who made significant contributions in a remarkably wide range of earth and natural science disciplines, including comparative anatomy, parasitology, and paleontology. As the Father of American Vert[e]brate Paleontology, he described not only the first relatively complete dinosaur skeleton, but the diversity of fossil finds in the American West. His knowledge of comparative anatomy enabled him to make sense of even fragmentary fossil remains. He was also a competant microscopist, scientific illustrator, and published papers in human biology and medicine. His microscopic examination of parasite cysts in cooked ham and microorganisms in housefly mouthparts enabled him to improve public heath.
William Lonsdale (Born 9 Sep 1794; died 11 Nov 1871). English geologist and paleontologist whose study of coral fossils found in Devon, suggested (1837) certain of them were intermediate between those typical of the older Silurian System (408 to 438 million years old) and those of the later Carboniferous System (286 to 360 million years old). Geologists Roderick Murchison and Adam Sedgwick agreed. They named (1839) this new geologic system after its locale – the Devonian System. Lonsdale’s early career was as an army officer (1812-15) and later he became curator and librarian of the Geological Society of London (1829-42). He recognised that fossils showed how species changed over time, and more primitive organisms are found in lower strata. Darwin used this to support his evolution theory.
Andreas Franz Wilhelm Schimper (Died 9 Sep 1901; born 12 May 1856). German botanist whose Pflanzentogeographie (1898) was one of the first and finest mapping of the floral regions of the continents. He coined (1885) the term chloroplasts (the organelles in plant cells that conduct photosynthesis), and distinguished them from chromatophores (pigment-containing cells found in many marine animals). In 1880, he proved that starch is the source of stored energy for plants. His explorations included Florida, the West Indies, South America, and Indonesia. On the Valdivia expedition (1898) he studied the oceanic plankton of numerous oceanic islands and coastal Africa. His father, Wilhelm Philipp Schimper was an expert on mosses and whose cousin Karl Friedrich Schimper studied plant morphology.