Edo Period guide to Kappa
This is an illustrated guide to 12 types of kappa (called the Suiko juni-hin no zu) that was produced in the Edo period in japan. The images were largely copied from older illustrations, and gives a good general idea of what a kappa was thought to look like in ancient Japan.
This copy of the image was taken from the Pink Tentacle website, which has lots of great articles on Japanese monsters and weirdness: Link Here.