PREFACE vii 



To my colleague, Mr. William Rowan, I am indebted for the 

 originals-of figures 3, 4, 6, 7, 91, and 93. The remaining figures have 

 been drawn for this work from preparations or from the original 

 papers. My former colleague, Dr. Katherine M. Parker, kindly 

 read through much of the manuscript of the early chapters. Messrs. 

 Bell and Sons, the publishers, have given me much assistance and 

 consideration. Lastly, my wife has helped me in many ways, not the 

 least of which was the preparation of the index. To all of these I 

 wish to express my sincere gratitude and thanks. 



In spite of good intentions, errors have doubtless crept in, and 

 I should be glad if these are brought to my notice. 



The book is for the use of students, most of whom will be pursuing 

 courses in allied sciences, and I trust that they will, be able to obtain 

 from it a sound introduction to Vertebrate Zoology, and some know- 

 ledge of and interest in the general principles of that science. Much 

 of any good it may contain is due indirectly to the excellent courses 

 given by Professor A. Dendy, F.R.S., and Professor J. P. Hill, F.R.S., 

 of the University of London, to both of whom the author is deeply 

 indebted. In the case of Professor Hill, moreover, my indebted- 

 ness is more direct, since, for several years, I was in charge of the 

 practical classes accompanying his lectures, and so had an 

 opportunity of becoming familiar with them. This was of con- 

 siderable advantage to me in preparing the book, parts of which are 

 more or less directly based upon his lecture-notes ; and I desire, 

 therefore, to express to him my sincere thanks. 



CHAS. H. O'DONOGHUE. 



UNIVERSITY OF MANITOBA, 



WINNIPEG, 



September^ 1920. 



