"Anis del Mono" was (and still is today) a well known brand of anisette in Spain. The name translates to "Monkey Anisette."
When Darwin came out with his (now proven) theory of evolution, the whole world made him to be a fool because he said that man and monkey share a common ancestor. Anis del Mono company owners, who apparently believed in the traditional views of things, changed the cute monkey in the original logo to a caricature of Charles Darwin. That modified logo remains until today.
Here's a larger image of the rebranded label.