the Anurans: Contemporary Research on Major Problems. University of Missouri Press, Columbia. External links AmphibiaWeb Gallery of Frogs – Photography and images of various frog species The Whole Frog Project – Virtual frog dissection and anatomy "Disappearance of toads, frogs has some scientists worried" San Francisco Chronicle, 20 April 1992 Amphibian photo gallery by scientific name – Features many unusual frogs Scientific American: Researchers Pinpoint Source of Poison Frogs' Deadly Defenses Media Time-lapse video showing the egg's development until hatching Frog vocalisations from around the world – From the British Library Sound Archive Frog calls – From Manitoba, Canada 01 Articles containing video clips Extant Hettangian first appearances