The developing embryo of a freshwater snail stained with SYTO 40 blue-fluorescent nucleic acid stain (S11351), a component of the SYTO Blue Fluorescent Stain Sampler Kit (S11350). A series of z-plane images was acquired with a wide-field optical sectioning confocal microscope. A three-dimensional volume rendering was generated from the deconvolved image series. Image contributed by Bruce Roth and Paul Millard, Molecular Probes, Inc., and Hillary MacDonald, Applied Precision, Inc.