A few early cleavages after fertilization in Saccoglossus Kowalevskii (acorn worm). Recorded in ~21 deg C temperature, at 2 frames per minute, reconstructed at 2 frames per second, so accelerated 60 times compared to real time.

Made on Sep 2012, MBL Woods Hole on "Nikon SMZ 1500" microscope with Plan Apo 1X WD70 Nikon lens at 2X magnification which gives approximately 2 um (.0021 mm) per pixel.