Figure 2

Lepisosteus osseus. Stages 1-5. A) Stage 1 showing egg envelopes. B) Stage 1 without egg envelopes, showing the dimple at the animal pole. C) Stage 2, two cells. D) Stage 3, four cells. E) Stage 4, eight cells. F) Stage 5, 16 cells. j = egg jelly ch = chorion ps = perivitelline space m = micropyle ap = animal pole b = blastodisc/blastoderm margin 1 = first cleavage furrow 2 = second cleavage furrow 3 = third cleavage furrow