I have terrible insomnia. So I've been wandering the web (its after 4am!) and I found an entire high-res version of Artforms of Nature by Ernst Haeckel on flickr. There is also a link to download the entire book as a pdf. I'm very happy. My hard copy version of this book seems to be an abridged collection and is missing many of the illustrations.
Artform of Nature by Ernst Haeckel
Ernst Haeckel was a German biologist and these illustrations were published between 1899-1904. I love them, so intricate and beautiful, yet also scientifically accurate.