W, W. SWINGLE 171 



ception is not sufficiently broad to account for the fundamental 

 changes incident to anuran transformation. For in these animals 

 metamorphosis usually implies complete shedding of the tadpole 

 characters, such as the fish-like tail, larval mouth, gills, intestinal 

 hystolysis, and reorganization and development of the frog character 

 by growth of limbs and other fundamental changes. Whether or not 

 the autolytic action of iodine is responsible for all these body changes 

 can only be determined by future investigation. 



There are unquestionably other unknown chemical factors involved 

 in the degenerative and regenerative processes involved in metamor- 

 phosis, and as investigation in this field has scarcely begun, all generali- 

 zations should be regarded as premature. 



In conclusion the writer wishes to acknowledge his indebtedness to 

 Professor E. N. Harvey and Professor E. G. Conklin for valuable 

 criticism and advice. 



