Octopus Under the Shelter of Rocks, 1961, by Olga Khludova (1913-1975), Soviet marine biologist & artist, wife of fellow zoologist-artist Nikolai Nikolaevich Kondakov (1908-1999), and apparently one of the first female scuba divers (along with Olga Zhukova) in the USSR? State Darwin Museum, Moscow, Russia. [Via Google Arts & Culture]

It's difficult to find much info on her in English, and even harder to find more art...here is a page which has low-res scans of color plates from her 1963 book Beyond the Blue Threshold, including another octopus: https://coollib.com/b/198822-olga-florentevna-hludova-za-golubyim-porogom/image