Figure 1.

Early egg development. A) Untouched, unfertilized egg. The surface of the egg under the jelly coat is featureless. B) Sperm-activated egg at six hours post-fertilization at the four-cell stage. Note the straight, ordered cleavage pattern (arrow). C) Artificially activated egg pseudocleaving. Note the jagged and disorganized cleavage pattern (arrow). D) An egg pseudocleaving at 16 hours. This egg was not handled and did not cleave within the first ten hours after deposition. At ten hours it was poked, and started pseudocleavage shortly thereafter (arrow). Scale bar = 1 mm.