Scientific Illustration Resources
Zoology, Animals, Herpetology, and Paleontology: R
Regenfuss, Franz Michael (1713 - 1780)
Reuwich, Erhard (fl. 1483)
Strange Science: The Rocky Road to Modern Paleontology and Biology
Richard, John H.
Antiquariaat Junk: John H. Richard
Richter, Henry Constantine (1821-1902)
Employed by John Gould after Elizabeth Gould died.
Wikipedia: Henry Constantine Richter
Cornell: Henry Constantine Richter
The Mammals of Australia
Roesel (Rosel) von Rosenhof, August Johann (1705-1759)
Frog Lifecycle: A. J. Roesel van Rosenhof
Ruini, Carlo (fl. 1598)
16th Century: Carlo Ruini
National Institutes of Health: Carlo Ruini