Holographic motion pictures provide a means for recording and observing transient, dynamic, small-scale events occurring at unpredictable times and locations in a given volume of space. Using an argon ion laser to generate repetitive pulses of 50 $\mu $s duration at a wavelength of 514.5 nm (5145 angstrom), holographic movies of living marine plankton organisms were produced by recording a series of in-line holograms at 70 frames/s on 35 mm film. The reconstructed holographic images may be viewed with a standard microscope, photographed with a still camera, or copied with a conventional movie camera for subsequent projection. Image resolution of 10 $\mu $m was obtained.