VI. Croonian lecture.— The evolution and origin of the amphibia

Abstract The problem of the origin of the Amphibia is one which necessarily attracted the attention of zoologists during the period which immediately succeeded the publication of the “Origin of Species.” Involving as it does the study of the most fundamental change in conditions of life which has occurred in the long history of the vertebrate animals, it still remains the most fascinating of all the problems of Phylogeny. It is possible to view the problem as purely one of formal morphology, the establishment of a series of stages which show intermediates between typical fish structures and those of the homologous organs in Amphibia may be regarded as a solution.