PREFACE. 



WITHIN recent years the laboratory method has become the 

 basis of instruction in every science. The student is expected 

 to find out a certain number of fundamental facts directly from 

 nature, but while this has in itself great value as a training in 

 observation, the fullest benefit of the study is not obtained 

 unless there be a comprehension of the bearings of the facts 

 observed. Observation and uncorrellated facts do not make a 

 science. Attention can be directed to the relations and signifi- 

 cance of the facts ascertained in the laboratory by means of 

 lectures, but a somewhat extended experience has shown that 

 the average student needs something more than his lecture 

 notes, at least when beginning any subject. The present volume 

 is intended to supplement both lectures and laboratory work, 

 and to place in concise form the more important facts and gen- 

 eralizations concerning the vertebrates. It is also hoped that 

 it may have some value for students of medicine in explaining 

 many peculiarities of the , structure of man which seem mean- 

 ingless unless viewed in the light of comparative morphology. 

 When once their meaning is comprehended it is easy to remem- 

 ber them. 



The first part of the volume is devoted to an outline of the 

 morphology of vertebrates based upon embryology. This treat- 

 ment has been adopted, since the author believes that in this 

 way the bearings of the facts can be most clearly shown and 

 most easily remembered. The remainder of the volume pre- 

 sents an outline of the classification of vertebrates, a subject 

 which, in recent years, has been too much ignored in college 

 work. Here the fossils are included as well as the recent 

 forms, since the existing fauna must be studied in the light of 

 the past. Numerous generic names have been mentioned with- 

 out characterization ; they have been inserted in order that the 

 student may be able to ascertain the relationships of the forms 

 he may find mentioned in collateral reading. 



