This is a vintage scientific illustration depicting luminous protozoa, specifically *Noctiluca*. The image is rendered in a detailed, engraved style with a dark background. **Composition:** The bottom portion of the image features a large, semi-circular shape representing a concentration of *Noctiluca* in water. It appears as a dense field of tiny, glowing dots, creating a luminous effect. Above this, a hand in a dark suit sleeve is holding a small glass or vial, seemingly containing a sample of the protozoa. **Magnified Views:** Two magnified views of *Noctiluca militaris* are presented. One is labeled as “magnified 100 diameters” and shows a complex, star-shaped internal structure within a rounded cell. The other, labeled “slightly magnified,” shows a simpler, more rounded cell with a visible nucleus. A third, even more magnified view shows the internal structure of the protozoa in great detail. **Style and Tone:** The illustration has a scientific and educational tone, typical of vintage biological illustrations. The use of detailed engraving and the dark background emphasize the luminous quality of the protozoa. The text labels provide scientific names and magnification levels, adding to the informative nature of the image.