EMBRYONIC DEVELOPMENT 221 



Prentiss, C. W., and L. B. Arey. A Laboratory Manual and Textbook of Embry- 

 ology. W. B. Saunders Company. (Chaps. I and II.) 



Spemann, H. Embryonic Development and Induction. Yale University Press. 



WiEMAN, H. L. An Introduction to Vertebrate Embryology. McGraw-Hill Book 

 Company, Inc. (Chaps. Ill and IV, early development of the amphioxus, frog, 

 and chick.) 



