Juergen Freund / Common Frog egg (frogspawn) with developoing embryo (Rana temporaria) Germany

Jane Burton / Common Frog (Rana temporaria) tadpoles developing in spawn

Doug Wechsler / Spotted salamander eggs {Ambystoma maculatum} with symbiotic algae, Delaware, USA

Juergen Freund / Eggcase of Swell shark showing embryo. (C. ventriosum) Pacific Cephaloscyllium

Morley Read / Close-up of Leaf frog (Cruziohyla craspedopus) tadpoles developing within an egg membrane, blood is circulating in the gills. Pastaza Province, Ecuador. (non-ex)

Morley Read / Close-up of Leaf frog (Cruziohyla craspedopus) tadpoles developing within an egg membrane, blood is circulating in the gills. Pastaza Province, Ecuador. (non-ex)

Morley Read / Glass frog (Centrolenidae) tadpoles developing in an egg mass, Cordillera del Condor, Zamora Chinchipe Province, Ecuador. (non-ex)

Morley Read / Glass frog (Centrolenidae) tadpoles developing in an egg mass, Cordillera del Condor, Zamora Chinchipe Province, Ecuador. (non-ex)

Morley Read / Glass frog (Centrolenidae) tadpoles developing in an egg mass, Cordillera del Condor, Zamora Chinchipe Province, Ecuador. (non-ex)

Morley Read / Close-up of Agua rica leaf frog (Phyllomedusa ecuatoriana) eggs after 18 days development, the tadpoles are fully developed and ready to hatch, Ecuador. Endangered. (non-ex)

Morley Read / Close-up of Agua rica leaf frog (Phyllomedusa ecuatoriana) eggs after 18 days development, the tadpoles are fully developed and ready to hatch, Ecuador. Endangered. (non-ex)

Morley Read / Close-up of Agua rica leaf frog (Phyllomedusa ecuatoriana) eggs after 18 days development, the tadpoles are fully developed and ready to hatch, Ecuador. Endangered. (non-ex)