Kay Nielsen's concept art for "the Little Mermaid"

This is not concept art for Ariel's movie.

Kay Nielsen painted these in the 1940s, for a project that wound up being shelved for 40 years. Disney had originally planned to make a collection of shorts based on Hans Christian Andersen's fairy tales, with "the Little Mermaid" being just one segment.

The above website has the full collection, but here are a few of my personal favorites: