A - Egg; dark center is yolk surrounded by a jelly-like vitallene
envelope which absorbs water and swells to a large size. This envelope
serves as a protective covering.
B - Tadpole; with gills and tail but no legs, latter beginning to form
at base of tail.
E (below) - Frog just about completely metamorphosed and an adult in habit and
appearance; only a bare remnant of the tail remaining.
C (above) - Fore and hind legs develop at about the same time; gills are
absorbed into the body and the frog now breathes through a pore designed
for that purpose. Tail remains, however, until later.
F - Fully grown adult frog that has been lucky in
evading, from the egg to adult stage, the many enemies that prey upon
these animals. Only a small percentage of the many eggs laid ever reach