PREFACE vii 



I am indebted to Professor Jacob Reighard for several 

 suggestions and criticisms in connection with the prepara- 

 tion of this work ; to Dr. W. P. Lombard for reading and 

 criticising several of the chapters dealing with the physi- 

 ology of the frog; and to Dr. J. E. Duerden for generously 

 undertaking the labor of critically reading the whole of 

 the manuscript before it went to press. To Dr. Ernst 

 Gaupp and his publisher, Friedrich View^eg, I wish to 

 express my thanks for their permission to reproduce sev- 

 eral of the figures in Gaupp's revision of Ecker and 

 Wiederscheim's "Anatomie des Frosches." 



