viii PREFACE TO FIRST EDITION 



incorporate much new work, especially from the neurological studies 

 of Johnston and Herrick. Further exact studies on these same general 

 morphological lines made possible the books of Goodrich (1930) and 

 de Beer (1935), which have provided the morphological background 

 for the present work. Throughout these works on Comparative Ana- 

 tomy the emphasis is on the evolution of the form of each organ 

 system rather than on the change of the organization of the life of 

 the animal as a whole. 



Meanwhile many other treatises appeared dealing with the life and 

 habits of the animals, rather than with morphological principles. 

 Among these we may mention Bronn's Tierreich (1859 onwards), the 

 Cambridge Natural History, and many works dealing with particular 

 groups of vertebrates. The palaeontologists produced their own series 

 of textbooks, mainly descriptive, such as those of Zittel and Smith 

 Woodward, culminating in Romer's admirably detailed and concise 

 book, to which the present work owes very much. The results of 

 embryological work have been summarized by Graham Kerr (191 9), 

 Korscheldt and Heider (1931), Brachet (1935), Huxley and de Beer 

 (1934), and Weiss (1939), among others. Unfortunately there has been 

 little summarizing of what is commonly called the comparative physio- 

 logy of vertebrates. Winterstein's great Handbuch der vergleichenden 

 Physiologie (191 2) covers much detailed evidence, but comes no nearer 

 than do the comparative anatomists to giving us a picture of the 

 evolution of the life of the whole organism. 



All of these books deal in some way with the evolution of vertebrates, 

 and vet curiously enough they speak of it very little. It is hardly an 

 exaggeration to say that they leave the student to decide for himself 

 what has been demonstrated by their studies. Huxley's Anatomy of 

 Vertebrated Animals (1871) is an exception in that it deals with the 

 animals rather than their parts, and at a more popular level. Brehm's 

 Thierleben (1876) gives a picture of the life of the animals, though in 

 this case not of their underlying organization. Kukenthal's great 

 Handbuch der Zoologie has the aim of synthesizing a variety of know- 

 ledge about each animal-group, and some of the volumes dealing with 

 vertebrates make fascinating reading- — notably that of Streseman on 

 birds. But the size of the work and the multiplicity of authors make 

 it impossible for any general picture of vertebrate life to appear from 

 the mass of details. 



The position is, then, that we have good descriptions of the struc- 

 ture, physiology, and development of vertebrates, of the discoveries 

 of the palaeontologists and accounts of vertebrate natural history, but 



