A tadpole embryo of the European edible frog, Rana temporaria, developing within its transparent egg. After hatching the young tadpole remains attached to the gelatinous egg envelope while further development occurs; a membrane grows over the external gills, the eyes become functional, the mouth & anus break through and the tail elongates. The larva finally develops into a free-swimming tadpole which feeds mainly on algae. Gradually the legs & lungs begin to develop and the gills and tail degenerate until the tadpole leaves the water as a fully-formed frog.