C. 1940s Microphoto of Water Flea, Signed Gene Gaines

I'm a sucker for a micrograph--a photo shot through a microscope--sometimes looking like pure abstractions, but here lending a sense of menacing magnitude to the tiny head of what I believe is a water flea. C. 1940s or so and signed George Gaines I believe on reverse.

4" x 4 1/8, good condition. Eggshell texture to the photo paper.