(Probably Euroleon nostras, app. 30mm long)
Experiment using Nikkor 50mm f1.8 lens with nikon BR-2A reversing ring, 56mm Kenko ext. tubes and Kenko 1.4 T/C. Also used was Nikon SB600 flash with homemade diffuser.
Because reversing ring is used, aperture is not controlled through camera, therefore is not recorded in exif data. Aperture is controlled manually.
Approx. magnification ratio 1.97:1
Handheld, so not as sharp as it could have been.