From the egg, then, the individual developed slowly into a higher form, just as the frog's egg develops through various stages from a fish with gills to a frog with lungs. View in context The canoe whirled with each cunning evolution of the chase, like a bubble floating in a whirlpool;...
lungs, Organs of breathing of vertebrate animals from adult amphibians through mammals.lymph, Part of the blood serum which is outside the blood vessels; bathes the cells.lysosomes, Contain digestive enzymes in animal cells.Mmaggot, Larval stage in the metamorphosis of the common housefly....