Original watercolours donated by Cornelius Sittardus to Conrad Gesner, and published by Gesner in his (1558-1670) works on aquatic animals

Some original watercolours, that were donated by the sixteenth century physician Cornelius Sittardus, to Conrad Gesner, who published them in his "Historia Animalium Liber IV(1558), at present are kept in the National Museum of Natural History of Leiden. These watercolours are discussed here, as well as the other figures of the Sittardus collection published by Gesner.