The Greeks called the crocodile the “pebble worm” because they saw it basking on the stones. The Romans named the viper for the way it gives birth. Linnaeus, faced with the largest animal that ever lived, christened it musculus, little mouse.

Every scientific name is a sentence spoken by someone seeing that animal for the first time. Arca gathers those sentences, and beside each one places the animal that inspired it: where it lives, how it is built, and the thing about it you would never expect.