Kind of reminiscent of the pearl diver and octopus
in Japanese woodblock prints.
Yeah, that’s what I was thinking of. That kind of art has inspired all sorts of modern “erotica” based on it in Japan, but the early stuff dates to the 19th century, so an artist in 1906 might have been familiar with it.
I was thinking of posting an image from wikipedia of that famous woodcut to show the similarity, but even though it’s “art”, the mods would probably frown on the graphic nature...