PREFACE ix 



The present volume deals with animal organisation as re- 

 presented by the Frog, with the Protozoa, and the Ccelenterata. 

 The second volume will deal with the Ccelomate Metazoa. 

 I had hoped to bring out the two volumes simultaneously, but 

 have been called out on military duty since the outbreak of 

 the war in S. Africa, so the completion of the second volume 

 has been delayed. 



GILBERT C. BOURNE. 



THE BARRACKS, TIPPERARY, 

 March 1900. 



PREFACE TO THE SECOND EDITION 



IN the course of the nine years that have elapsed since this 

 volume was published many and noteworthy additions have 

 been made to all branches of Zoological Science. Conse- 

 quently a new edition, embodying such important discoveries 

 as may properly find a place in an elementary text-book, has 

 become necessary. The original plan of the work has not 

 been altered, and many of the chapters remain in practically 

 the same state as in the first edition. The portion of 

 Chapter III. relating to Mitosis, the Maturation of the Ovum,, 

 Spermatogenesis and Fertilisation has been rewritten, as has 

 also the chapter on Monocystis. A considerable amount of 

 new matter has been introduced into the chapters on Amoeba 

 and Paramecium, and the life-history of Copromonas subtilis 

 has been substituted for Dallinger and Drysdale's doubtful 

 account of the life-history of Bodo. In order that the volume 

 may be more serviceable to medical students, who form the 

 majority of the students of Elementary Comparative Anatomy 

 in this country, I have added a chapter on Malaria and the 

 life-history of the Malarial Parasite which will, I hope, afford 

 a useful introduction to the study of the Pathogenic Protozoa. 

 As the volume seemed to be rather overweighted with descrip- 

 tions of Protozoa, it was my intention to omit the chapters on 

 Actinosphaerium and Badhamia, but on the advice of friends 



