Above, a swift, a swallow, a hyrax, an insect, a hippopotamus and a porcupine; below, two insect and a caterpillar and three reptiles, including a crocodile. Engraving by Heath.

Licence: Public Domain Mark

Credit: Above, a swift, a swallow, a hyrax, an insect, a hippopotamus and a porcupine; below, two insect and a caterpillar and three reptiles, including a crocodile. Engraving by Heath. Wellcome Collection. Source: Wellcome Collection.