The Xenopus egg is surrounded by a dense elastic jelly so that it is not possible to penetrate into the egg cytoplasm with a micropipette, unless the jelly is removed or denatured by ultraviolet light. (A) Side view. (B) “Animal” pole; the white area in the middle of the black area is where the egg chromosomes are located. (C) If the egg is not de-jellied, a micropipette depresses the jelly coat, eventually dragging the pipette, still surrounded by jelly, through the egg without entering the cytoplasm (D).