iv VERTEBRATE ZOOLOGY 



specimen is needed for a study of the outer form and the viscera, 

 including the heart and its principal vessels, one specimen for the 

 complete dissection of the blood vessels, and one for the skeleton. 

 In case material is scarce or expensive, however, the study can 

 always be abbreviated and the most important organs be studied 

 with a single specimen. On the other hand, if material is abun- 

 dant, it will often be convenient to use more than the number of 

 specimens mentioned. 



The author recognizes the great importance as well as the great 

 difficulty of rendering a book of this kind free from errors, and 

 has, accordingly, sought to secure as high a degree of accuracy 

 as possible. To all who have assisted and advised him he returns 

 hearty thanks ; especially to Professor Karl Heider, of the Univer- 

 sity of Innsbruck, in whose laboratory the greater part of the book 

 was written. He will also be under the greatest obligation to 

 teachers and students who will tell him of any mistakes of fact 

 they may find, or of improvements which may suggest themselves 



to them. 



H. S. PRATT 

 Haverford, Pennsylvania 



PREFACE TO THE REVISED EDITION 



The object of this revision is to correct certain errors of fact 

 which use of the book has revealed, and also to provide the addi- 

 tion of directions for the dissection of the rabbit, which is preferred 

 to the cat by many teachers as a representative of the mammals. 

 The structure of the guinea pig and rat is so similar to that 

 of the rabbit that the directions can be used equally well for 

 these animals. 



