PREFACE TO 

 THE FIRST EDITION 



The history of textbooks is often dismissed by the contemptuous 

 assertion that they all copy each other — and especially each other's 

 mistakes. Inspection of this book will quickly confirm that this is true, 

 but there is nevertheless an interest to be obtained from such a study, 

 because textbooks embody an attitude of mind; they show what sort 

 of knowledge the writer thinks can be conveyed about the subject- 

 matter. It may be that they are more important than at first appears 

 in furthering or preventing the change of ideas on any theme. 



The results of the studies of scholars on the subject of vertebrates 

 have been summarized in a series of comprehensive textbooks during 

 the past hundred years. Most of these works are planned on the lines 

 laid down by the books of Gegenbaur (1859), Owen (1866), and 

 Wiedersheim (1883), lines that derive from a pre-evolutionary tradi- 

 tion. This partly explains the curiosity that in spite of the great impor- 

 tance of evolutionary doctrine for vertebrate studies, and vice versa, 

 vertebrate textbooks often do not deal directly with evolution. They 

 derive their order from something even more fundamental than the 

 evolutionary principle. The essential of any good textbook is that it 

 should be both accurate and general. As Owen puts it in his Preface: 

 Tn the choice of facts I have been guided by their authenticity and 

 their applicability to general principles.' The chief of the principles 

 he adopted was 'to guide or help in the power of apprehending the 

 unity which underlies the diversity of animal structures, to show in 

 these structures the evidence of a predetermining Will, producing 

 them in reference to a final purpose, and to indicate the direction and 

 degrees in which organisation, in subserving such Will, rises from the 

 general to the particular'. He confessed 'ignorance of the mode of 

 operation of the natural law of their succession on the earth. But that 

 it is an "orderly succession" — and also "progressive" — is evident 

 from actual knowledge of extinct species.' 



These principles were essentially sound, and Owen's treatment was 

 to a large extent the basis of the work that appeared after the Dar- 

 winian revolution. In English, following the translation of Wieder- 

 sheim's book by W. N. Parker (1886) we have H. J. Parker and 

 Haswell's work, now in its 6th edition. The books of Kingsley and 

 Neal and Rand are in essentially the same tradition, though they 



