PREFACE TO THE NINTH EDITION. 



A few alterations have been made in this revised edition. The 

 account of the Tapeworm and the figures illustrating it are 

 new and are based upon the commonest form occurring in the 

 Dog. The nomenclature of the Vertebrate Kidney, always 

 a very difficult subject, has been revised, though I have not 

 used the term ' opisthonephros,' suggested by Professor 

 Graham Kerr for the kidney of fishes, as the use of that term 

 implies a theoretical assumption that should be avoided when 

 one is dealing with students. 



I wish to acknowledge the kind assistance of Mr. F. J. 

 Meggitt, M.Sc, and of Mr. Harold Jackson, M.Sc. 



F. W. Gamble. 

 February, 1920. 



