Histological aspects of metamorphosis of Ambystoma tigrinum (green)

The present paper is based upon research done in 1933 at the University of Utah. The specimens used in the study were of the common species of salamander frequenting this region, Ambystoma tigrinum. This report is confined to the histological changes observed in the lungs and skin of this form during the process of metamorphosis. Special attention will be given to the origin of the poison glands of the skin. Further observations on the external and physiological aspects of metamorphosis will be submitted at a later date. The author wishes to acknowledge the very valuable assistance given him by Dr. R. V. Chamberlin and by Mr. W. W. Newby of the Zoology Department of the University of Utah.