Hatchlings walking
  three hatchlings walking under polarized light
Chromosomes in meiosis
  diploid chromosome number is 10
Early cell divisions in two embryos
  twelve hours of development in one plane
Multiplane film of early cell divisions in two embryos
  twelve hours in four planes, from a 20-plane film
Internalization of surface cells, viewed from ventral surface
  three of the four cells with asterisks internalize at the 60-cell stage
Internalization of surface cells, viewed from ventral surface, colored
  same as above, with four cells colored. One of the two green cells moves in, then two purple cells
Muscle movements begin in five embryos
  bright spots are birefringent granules in the midgut cells
Laser ablation of early cells
  laser-ablated cells stop brownian motion, other cells continue dividing
Laser ablation of later epithelial cells
  laser-ablated cells stop brownian motion, other cells continue dividing