Above, an insect, a musk rat, a siren (eel-shaped taile amphibian), and two hawk moths; below, a shark, a sponge, a vertebrate, an owl, a noddy (a tropical sea bird) and a stapelia. Engraving by Heath.

Licence: Public Domain Mark

Credit: Above, an insect, a musk rat, a siren (eel-shaped taile amphibian), and two hawk moths; below, a shark, a sponge, a vertebrate, an owl, a noddy (a tropical sea bird) and a stapelia. Engraving by Heath. Wellcome Collection. Source: Wellcome Collection.