IV PREFACE. 



has shown that beginners rarely go to the original sources. This 

 omission is the less important since in all schools where the book is 

 likely to be used other works containing good bibliographies are 

 accessible. Eeference might here be made to those in the Anat- 

 omies of Lang and Wiedersheim, the Embryologies of Balfour, 

 Korschelt and Heider, Minot, and Hertwig, and Wilson's work on 

 The Cell. 



The editor must here return his thanks to Dr. George W. Field 

 for his kindness in allowing the use of his translation of the first 

 part of the book as the basis of the present edition. 



J. S. KINGSLEY. 

 TUFTS COLLEGE, MASS., Sept. 19, 1902. 



