3320. The Frog Embryology (Rana sp.). 20 Color Photomicrographs. 1. Egg, two-cell stage t.s. 2. Egg, four-cell stage t.s. 3. Egg, eight-cell stage l.s. 4. Morula l.s. 5. Blastula l.s. 6. Early gastrula l.s. 7. Late gastrula l.s. 8. Early neurula t.s. 9. L